Washington, D.C. 20549



Investment Company Act file number: (811- 05901 )

Exact name of registrant as specified in charter: Putnam Investment Grade Municipal Trust

Address of principal executive offices: One Post Office Square, Boston, Massachusetts 02109

Name and address of agent for service:  Beth S. Mazor, Vice President 
  One Post Office Square 
  Boston, Massachusetts 02109 
Copy to:  John W. Gerstmayr, Esq. 
  Ropes & Gray LLP 
  One International Place 
  Boston, Massachusetts 02110 
Registrant’s telephone number, including area code:  (617) 292-1000 

Date of fiscal year end: November 30, 2006

Date of reporting period: August 31, 2006

Item 1. Schedule of Investments:

Putnam Investment Grade Municipal Trust       

The fund's portfolio       
8/31/06 (Unaudited)       
Key to abbreviations       
AMBAC -- AMBAC Indemnity Corporation       
COP -- Certificate of Participation       
FGIC -- Financial Guaranty Insurance Company       
FHA Insd. -- Federal Housing Administration Insured       
FHLMC Coll. -- Federal Home Loan Mortgage Corporation Collateralized       
FNMA Coll. -- Federal National Mortgage Association Collateralized       
FSA -- Financial Security Assurance       
GNMA Coll. -- Government National Mortgage Association Collateralized       
G.O. Bonds -- General Obligation Bonds       
MBIA -- MBIA Insurance Company       
PSFG -- Permanent School Fund Guaranteed       
U.S. Govt. Coll. -- U.S. Government Collateralized       
VRDN -- Variable Rate Demand Notes       
XLCA -- XL Capital Assurance       
MUNICIPAL BONDS AND NOTES (160.8%)(a)       
  Rating (RAT)  Principal amount  Value 

Alabama (0.2%)       
Sylacauga, Hlth. Care Auth. Rev. Bonds (Coosa Valley       
Med. Ctr.), Ser. A, 6s, 8/1/25  B/P  $400,000  $416,476 

Arizona (1.6%)       
AZ Hlth. Fac. Auth. Hosp. Syst. Rev. Bonds (John C.       
Lincoln Hlth. Network), 6 3/8s, 12/1/37 (Prerefunded)  BBB  500,000  575,710 
Casa Grande, Indl. Dev. Auth. Rev. Bonds (Casa Grande       
Regl. Med. Ctr.), Ser. A, 7 5/8s, 12/1/29  BB-/P  1,175,000  1,306,577 
Pima Cnty., Indl Dev. Auth. Rev. Bonds (Horizon Cmnty.       
Learning Ctr.), 5.05s, 6/1/25  BBB-  525,000  511,308 
Scottsdale, Indl. Dev. Auth. Hosp. Rev. Bonds       
(Scottsdale Hlth. Care), 5.8s, 12/1/31 (Prerefunded)  A3  1,000,000  1,108,830 

Arkansas (2.2%)       
AR State Hosp. Dev. Fin. Auth. Rev. Bonds (Washington       
Regl. Med. Ctr.), 7 3/8s, 2/1/29 (Prerefunded)  Baa2  3,000,000  3,350,340 
Independence Cnty., Poll. Control Rev. Bonds (Entergy,       
Inc.), 5s, 1/1/21  A-  500,000  506,900 
Jefferson Cnty., Poll. Control Rev. Bonds (Entergy,       
Inc.), 4.6s, 10/1/17  A-  355,000  358,309 
Little Rock G.O. Bonds (Cap. Impt.), FSA, 3.95s, 4/1/19  Aaa  760,000  752,438 

California (20.4%)       
Anaheim, Pub. Fin. Auth. Tax Alloc. Rev. Bonds, MBIA,       
6.45s, 12/28/18  Aaa  4,000,000  4,225,040 
CA Edl. Fac. Auth. Rev. Bonds (U. of the Pacific), 5s,       
11/1/21  A2  525,000  551,318 
CA Hlth. Fac. Auth. Rev. Bonds (Sutter Hlth.), Ser. A,       
MBIA, 5 3/8s, 8/15/30  Aaa  2,500,000  2,591,925 
CA State G.O. Bonds       
5 1/8s, 4/1/23  A+  500,000  529,375 
5.1s, 2/1/34  A+  750,000  762,503 
CA State Dept. of Wtr. Resources Rev. Bonds, Ser. A       
6s, 5/1/15 (Prerefunded)  Aaa  1,500,000  1,697,295 
AMBAC, 5 1/2s, 5/1/13 (SEG)  Aaa  13,000,000  14,337,700 
5 1/2s, 5/1/11  A2  1,500,000  1,615,020 
CA State Econ. Recvy. G.O. Bonds, Ser. A, 5s, 7/1/16  Aa3  1,000,000  1,055,950 
CA Statewide Cmnty. Dev. Auth. COP (The Internext       
Group), 5 3/8s, 4/1/30  BBB  1,750,000  1,770,755 
Cathedral City, Impt. Board Act of 1915 Special Assmt.       
Bonds (Cove Impt. Dist.), Ser. 04-02, 5.05s, 9/2/35  BB+/P  270,000  272,225 
Chula Vista, Indl. Dev. Rev. Bonds (San Diego Gas),       
Ser. B, 5s, 12/1/27  A1  640,000  661,088 
Gilroy, Rev. Bonds (Bonfante Gardens Park), 8s, 11/1/25  B-/P  576,000  507,174 
Golden State Tobacco Securitization Corp. Rev. Bonds       
Ser. 03 A-1, 6 1/4s, 6/1/33  BBB  1,000,000  1,099,420 
Ser. B, FHLMC Coll., 5 5/8s, 6/1/38 (Prerefunded)  AAA  1,500,000  1,668,780 
Ser. 03 A-1, 5s, 6/1/21  BBB  420,000  421,919 
Orange Cnty., Cmnty. Fac. Dist. Special Tax Rev. Bonds       
(Ladera Ranch - No. 02-1), Ser. A, 5.55s, 8/15/33  BBB/P  450,000  462,573 
Riverside Cnty., Redev. Agcy. Tax Alloc., Ser. A,       
XLCA, 5s, 10/1/29  Aaa  4,700,000  4,899,374 
Roseville, Cmnty. Fac. Special Tax Bonds (Dist. No. 1       
- Westpark), 5 1/4s, 9/1/19  BB/P  875,000  900,883 
Roseville, Special Tax (Fiddyment Ranch Cmnty. Fac),       
Ser. 1, 5s, 9/1/20  BB/P  255,000  255,395 
Sacramento, Special Tax Bonds (North Natomas Cmnty.       

Fac.), 5s, 9/1/18                                                          BB/P 1,040,000 1,065,438  
Santa Clara Cnty., Fin. Auth. Lease Rev. Bonds       
(Multiple Fac.), Ser. I, AMBAC, 5s, 5/15/20  Aaa  3,000,000  3,231,390 
Vallejo, COP (Marine World Foundation), 7.2s, 2/1/26  BBB-/P  1,400,000  1,442,448 

Colorado (4.5%)       
CO Hlth. Fac. Auth. Rev. Bonds (Hlth. Fac. -       
Evangelical Lutheran), 3.35s, 10/1/06  A3  2,500,000  2,497,450 
CO Springs, Hosp. Rev. Bonds       
6 3/8s, 12/15/30  A3  1,515,000  1,658,395 
6 3/8s, 12/15/30 (Prerefunded)  A3  1,485,000  1,653,963 
CO State Hsg. Fin. Auth. Rev. Bonds (Single Fam.)       
Ser. B-2 , 7s, 5/1/26  Aa2  95,000  95,876 
Ser. B-3, 6.8s, 11/1/28  Aa2  50,000  50,165 
Denver, City & Cnty. Arpt. Rev. Bonds, MBIA, 5 1/2s,       
11/15/25  Aaa  2,500,000  2,534,075 
U. of CO. Enterprise Syst. Rev. Bonds, FGIC, 5s, 6/1/26  Aaa  1,650,000  1,745,585 

Delaware (0.7%)       
GMAC Muni. Mtge. Trust 144A sub. notes       
Ser. A1-3, 5.3s, 10/31/39  A3  500,000  523,145 
Ser. A1-2, 4.9s, 10/31/39  A3  1,000,000  1,024,930 

District of Columbia (1.8%)       
DC G.O. Bonds, Ser. B, FSA, 5 1/4s, 6/1/26  Aaa  4,000,000  4,153,680 

Florida (4.4%)       
Escambia Cnty., Hlth. Fac. Auth. Rev. Bonds (Baptist       
Hosp. & Baptist Manor), 5 1/8s, 10/1/19  Baa1  1,895,000  1,933,866 
Halifax, Hosp. Med. Ctr. Rev. Bonds, Ser. A, 5 1/4s,       
6/1/19  BBB+  2,200,000  2,328,766 
Highlands Cnty., Hlth. Fac. Auth. Rev. Bonds       
(Adventist Hlth.), Ser. A, 5s, 11/15/23  A+  300,000  312,087 
Lee Cnty., Indl. Dev. Auth. Rev. Bonds (Alliance       
Cmnty.), Ser. C, 5 1/2s, 11/15/29  BBB-  1,000,000  1,022,990 
Miami Beach, Hlth. Fac. Auth. Hosp. Rev. Bonds (Mount       
Sinai Med. Ctr.), 5 3/8s, 11/15/28  BB+  2,000,000  2,013,400 
Okeechobee Cnty., Solid Waste Mandatory Put Bonds       
(Waste Mgt./Landfill), Ser. A, 4.2s, 7/1/09  BBB  375,000  374,783 
Reunion West, Cmnty. Dev. Dist. Special Assmt. Bonds,       
6 1/4s, 5/1/36  BB-/P  850,000  895,679 
Tern Bay, Cmnty. Dev. Dist. Rev. Bonds, Ser. B, 5s,       
5/1/15  BB-/P  450,000  455,585 
Tolomato, Cmnty. Dev. Dist. Special Assmt. Bonds,       
5.4s, 5/1/37  BB-/P  175,000  177,037 
Wentworth Estates Cmnty., Dev. Dist. Special Assmt.       
Bonds, Ser. B, 5 1/8s, 11/1/12  BB-/P  465,000  470,371 

Georgia (5.4%)       
Atlanta, Arpt. Rev. Bonds, Ser. B, FGIC, 5 5/8s, 1/1/30  Aaa  1,500,000  1,576,170 
Atlanta, Wtr. & Waste Wtr. Rev. Bonds, Ser. A, FGIC,       
5s, 11/1/38 (Prerefunded)  Aaa  1,045,000  1,087,918 
Burke Cnty., Poll. Control Dev. Auth. Mandatory Put       
Bonds (GA Power Co.), 4.45s, 12/1/08  A2  2,300,000  2,336,570 
Cobb Cnty., Dev. Auth. U. Fac. Rev. Bonds (Kennesaw       
State U. Hsg.), Ser. A, MBIA, 5s, 7/15/29  Aaa  5,215,000  5,445,347 
GA Med. Ctr. Hosp. Auth. Rev. Bonds, MBIA, 6.367s,       
8/1/10  Aaa  600,000  600,678 
Rockdale Cnty., Dev. Auth. Solid Waste Disp. Rev.       
Bonds (Visay Paper, Inc.), 7.4s, 1/1/16  B+/P  1,155,000  1,158,684 

Hawaii (0.4%)       
HI State Hsg. & Cmnty. Dev. Corp. Rev. Bonds (Single       
Fam. Mtge.), Ser. B, 3.7s, 1/1/22  Aaa  900,000  892,935 

Idaho (0.2%)       
ID Hsg. & Fin. Assn. Rev. Bonds (Single Fam. Mtge.),       
Ser. C-2, FHA Insd., 5.15s, 7/1/29  Aaa  420,000  425,741 

Illinois (11.7%)       
Chicago, G.O. Bonds, Ser. A, FSA, 5s, 1/1/27  Aaa  4,270,000  4,461,211 
Chicago, Board of Ed. G.O. Bonds (School Reform), Ser.       
AMBAC, 5 1/4s, 12/1/27  Aaa  2,500,000  2,590,625 
FGIC, zero %, 12/1/18  Aaa  5,440,000  3,205,357 
Cook Cnty., Cmnty. G.O. Bonds (Cons. School Dist. No.       
64 Pk. Ridge), FSA, 5 1/2s, 12/1/16  Aaa  1,580,000  1,790,156 
IL Dev. Fin. Auth. Rev. Bonds (Midwestern U.), Ser. B,       
6s, 5/15/26  A-  1,600,000  1,740,240 

IL Dev. Fin. Auth. Hosp. Rev. Bonds (Adventist Hlth.       
Syst./Sunbelt Obligation), 5.65s, 11/15/24       
(Prerefunded)                                  A2 2,500,000 2,666,025     
IL State Toll Hwy. Auth. Rev. Bonds, Ser. A-1, FSA,       
5s, 1/1/23  Aaa  2,250,000  2,393,483 
IL U. Rev. Bonds (Auxiliary Fac. Syst.), Ser. A,       
AMBAC, 5 1/4s, 4/1/19  Aaa  1,945,000  2,185,344 
Schaumburg, G.O. Bonds, Ser. B, FGIC, 5s, 12/1/27  Aaa  5,000,000  5,247,350 

Indiana (1.7%)       
IN State Dev. Fin. Auth. Env. Impt. Rev. Bonds (USX       
Corp.), 5.6s, 12/1/32  Baa1  2,600,000  2,712,320 
Rockport, Poll. Control Rev. Bonds (Indiana-Michigan       
Pwr.), Ser. A, 4.9s, 6/1/25  Baa2  1,000,000  1,004,450 

Iowa (0.8%)       
IA Fin. Auth. Hlth. Care Fac. Rev. Bonds (Care       
Initiatives), 9 1/4s, 7/1/25  AAA/P  1,500,000  1,876,515 

Kansas (0.1%)       
Lawrence, Hosp. Rev. Bonds (Lawrence Memorial Hosp.),       
5 1/4s, 7/1/21  A3  250,000  266,575 

Louisiana (0.9%)       
Ernest N. Morial - New Orleans, Exhibit Hall Auth.       
Special Tax Bonds, Ser. A, AMBAC, 5 1/4s, 7/15/21  Aaa  1,500,000  1,586,520 
LA Pub. Fac. Auth. Rev. Bonds (Pennington Med.       
Foundation), 5s, 7/1/16  A3  400,000  420,248 

Maine (0.5%)       
ME State Hsg. Auth. Rev. Bonds, Ser. D-2-AMT, 5s,       
11/15/27  Aa1  1,185,000  1,204,268 

Massachusetts (11.1%)       
MA State Dev. Fin. Agcy. Rev. Bonds (MA Biomedical       
Research), Ser. C, 6 3/8s, 8/1/17  Aa3  2,785,000  3,036,068 
MA State Hlth. & Edl. Fac. Auth. Rev. Bonds       
(Civic Investments/HPHC), Ser. A, 9s, 12/15/15  BBB-/P  1,000,000  1,240,590 
(Jordan Hosp.), Ser. E, 6 3/4s, 10/1/33  BBB-  750,000  822,735 
(Med. Ctr. of Central MA), AMBAC, 6.55s, 6/23/22  Aaa  16,150,000  16,854,133 
(UMass Memorial), Ser. D, 5s, 7/1/33  Baa2  500,000  508,890 
MA State Hsg. Fin. Agcy. Rev. Bonds (Rental Mtge.),       
Ser. C, AMBAC, 5 5/8s, 7/1/40  Aaa  2,500,000  2,550,000 

Michigan (3.0%)       
Dickinson Cnty., Econ. Dev. Corp. Poll. Control Rev.       
Bonds (Intl. Paper Co.), Ser. A, 4.8s, 11/1/18  BBB  900,000  908,415 
Flint, Hosp. Bldg. Auth. Rev. Bonds (Hurley Med.       
Ctr.), 6s, 7/1/20  Ba1  75,000  79,460 
MI State Hosp. Fin. Auth. Rev. Bonds       
(Oakwood Hosp.), Ser. A, 5 3/4s, 4/1/32  A2  1,000,000  1,060,460 
(Holland Cmnty. Hosp.), Ser. A, FGIC, 5 3/4s, 1/1/21  A2  1,250,000  1,350,475 
MI State Hsg. Dev. Auth. Rev. Bonds, Ser. A, 3.9s,       
6/1/30  AA+  1,200,000  1,195,896 
Monroe Cnty., Hosp. Fin. Auth. Rev. Bonds (Mercy       
Memorial Hosp. Corp.), 5 3/8s, 6/1/26  Baa3  750,000  777,848 
Saginaw Cnty., G.O. Bonds (Healthsource Saginaw,       
Inc.), MBIA, 5s, 5/1/26  Aaa  1,210,000  1,270,597 

Minnesota (2.1%)       
Cohasset, Poll. Control Rev. Bonds (Allete, Inc.),       
4.95s, 7/1/22  A  2,500,000  2,545,250 
Minneapolis, Cmnty. Dev. Agcy. Supported Dev. Rev.       
Bonds, Ser. G-3, U.S. Govt. Coll., 5.45s, 12/1/31       
(Prerefunded)  A+  1,705,000  1,848,288 
St. Paul, Hsg. & Redev. Auth. Hosp. Rev. Bonds (Hlth.       
East), 6s, 11/15/25  Baa3  350,000  381,952 

Mississippi (2.5%)       
Lowndes Cnty., Solid Waste Disp. & Poll. Control Rev.       
Bonds (Weyerhaeuser Co.)       
Ser. A, 6.8s, 4/1/22  Baa2  500,000  604,445 
Ser. B, 6.7s, 4/1/22  Baa2  525,000  628,987 
MS Bus. Fin. Corp. Poll. Control Rev. Bonds (Syst.       
Energy Resources, Inc.), 5 7/8s, 4/1/22  BBB-  1,750,000  1,752,555 
MS Dev. Bk. Special Obligation Rev. Bonds (Jackson,       
MS), FSA, 5 1/4s, 3/1/21  Aaa  1,385,000  1,554,441 

MS Home Corp. Rev. Bonds (Single Fam. Mtge.), Ser.       
B-2, GNMA Coll., FNMA Coll., 6.45s, 12/1/33  Aaa  705,000  734,638 
MS Hosp. Equip. & Fac. Auth. Rev. Bonds (Hosp. South       
Central), 5 1/4s, 12/1/21  BBB+/F  250,000  263,548 

Missouri (2.2%)       
Cape Girardeau Cnty., Indl. Dev. Auth. Hlth. Care Fac.       
Rev. Bonds (St. Francis Med. Ctr.), Ser. A, 5 1/2s,       
6/1/16  A+  1,250,000  1,344,400 
MO Hsg. Dev. Comm. Rev. Bonds (Home Ownership), Ser.       
D, GNMA Coll., FNMA Coll., 5.55s, 9/1/34  Aaa  1,050,000  1,078,623 
MO State Hlth. & Edl. Fac. Auth. Rev. Bonds (BJC Hlth.       
Syst.), 5 1/4s, 5/15/32  Aa2  1,000,000  1,044,030 
MO State Hsg. Dev. Comm. Mtge. Rev. Bonds (Single Fam.       
Homeowner Loan)       
Ser. A-2, GNMA Coll., 6.3s, 3/1/30  AAA  785,000  812,530 
Ser. C, GNMA Coll., FNMA Coll., 5.6s, 9/1/35  AAA  670,000  709,671 

Nevada (3.8%)       
Clark Cnty., Arpt. Rev. Bonds, Ser. A-2, FGIC, 5 1/8s,       
7/1/26  Aaa  5,105,000  5,406,195 
Clark Cnty., Impt. Dist. Special Assmt. Bonds       
(Summerlin No. 151), 5s, 8/1/25  BB/P  700,000  708,183 
Henderson, Local Impt. Dist. Special Assmt. Bonds       
(No. T-16), 5.1s, 3/1/21  BB-/P  1,000,000  1,011,740 
(No. T-17), 5s, 9/1/25  BB/P  225,000  226,132 
(No. T-14), 4 3/4s, 3/1/10  BB/P  1,075,000  1,087,029 

New Hampshire (0.4%)       
NH State Bus. Fin. Auth. Poll. Control Rev. Bonds,       
3 1/2s, 7/1/27  Baa2  950,000  930,468 

New Jersey (5.5%)       
NJ Econ. Dev. Auth. Rev. Bonds       
(Cedar Crest Vlg., Inc.), Ser. A, 7 1/4s, 11/15/31  BB-/P  650,000  707,135 
(Cigarette Tax), 5 3/4s, 6/15/29  Baa2  1,750,000  1,878,975 
(Motor Vehicle), Ser. A, MBIA, 5s, 7/1/27  Aaa  5,000,000  5,260,550 
NJ State Rev. Bonds (Trans. Syst.), Ser. C, AMBAC,       
zero %, 12/15/24  Aaa  4,800,000  2,116,992 
NJ State Edl. Fac. Auth. Rev. Bonds (Fairleigh       
Dickinson), Ser. C, 6s, 7/1/20  BBB-/F  750,000  831,233 
Tobacco Settlement Fin. Corp. Rev. Bonds       
6 3/4s, 6/1/39  BBB  500,000  560,390 
6s, 6/1/37  BBB  1,000,000  1,061,010 

New Mexico (1.1%)       
Farmington, Poll. Control VRDN (AZ Pub. Service Co.),       
Ser. B, 3.47s, 9/1/24  P-1  1,300,000  1,300,000 
NM Fin. Auth. Rev. Bonds, Ser. A, MBIA, 5s, 6/15/22  Aaa  750,000  798,270 
NM Mtge. Fin. Auth. Rev. Bonds (Single Fam. Mtge.),       
Ser. D-2, GNMA Coll., FNMA Coll., FHLMC Coll., 5.64s,       
9/1/33  AAA  385,000  398,148 

New York (20.1%)       
NY City, G.O. Bonds, Ser. B, 5 1/4s, 12/1/09  AA-  7,780,000  8,149,005 
NY City, Hsg. Dev. Corp. Rev. Bonds, Ser. A, FGIC, 5s,       
7/1/25  Aaa  500,000  528,820 
NY City, Indl. Dev. Agcy. Rev. Bonds       
(Liberty-7 World Trade Ctr.), Ser. A, 6 1/4s, 3/1/15  B-/P  500,000  531,590 
(Brooklyn Navy Yard Cogen. Partners), Ser. G, 5 3/4s,       
10/1/36  BBB-  2,000,000  2,021,540 
NY City, Indl. Dev. Agcy. Special Fac. Rev. Bonds       
(British Airways PLC), 5 1/4s, 12/1/32  Ba2  250,000  236,708 
NY City, Muni. Wtr. & Swr. Fin. Auth. Rev. Bonds       
Ser. B, 5 3/4s, 6/15/26 (Prerefunded)  AA+  4,100,000  4,207,994 
Ser. D, 5s, 6/15/37  AA+  7,500,000  7,807,500 
NY State Dorm. Auth. Rev. Bonds (NY Methodist Hosp.),       
5 1/4s, 7/1/15  A3  500,000  536,030 
NY State Energy Research & Dev. Auth. Gas Fac. Rev.       
Bonds (Brooklyn Union Gas), 6.952s, 7/1/26  A+  2,000,000  2,058,520 
NY State Env. Fac. Corp. Rev. Bonds, 5s, 6/15/32  Aaa  4,000,000  4,184,320 
NY State Hwy. Auth. Rev. Bonds (Hwy. & Bridge Trust       
Fund), Ser. B, FGIC, 5s, 4/1/17  AAA  3,000,000  3,252,360 
Port. Auth. NY & NJ Special Oblig. Rev. Bonds (JFK       
Intl. Air Term. - 6), MBIA, 5.9s, 12/1/17  Aaa  10,500,000  10,962,210 
Suffolk Cnty., Indl. Dev. Agcy. Rev. Bonds (Peconic       
Landing), Ser. A, 8s, 10/1/30  B+/P  650,000  715,117 

North Carolina (3.4%)       
NC Eastern Muni. Pwr. Agcy. Syst. Rev. Bonds       
Ser. D, 6 3/4s, 1/1/26  Baa2  1,000,000  1,094,040 
Ser. A, 5 3/4s, 1/1/26  Baa2  2,000,000  2,111,780 
NC Med. Care Cmnty. Hlth. Care Fac. Rev. Bonds (First       
Mtge. - Presbyterian Homes), 5 3/8s, 10/1/22  BB/P  500,000  517,075 
NC State Muni. Pwr. Agcy. Rev. Bonds (No. 1, Catawba       
Elec.), Ser. B, 6 1/2s, 1/1/20  A3  3,500,000  3,820,460 

North Dakota (0.4%)       
ND State Board of Higher Ed. Rev. Bonds (U. of ND Hsg.       
& Auxillary Fac.), FSA       
5s, 4/1/21  Aaa  400,000  425,640 
5s, 4/1/19  Aaa  500,000  534,900 

Ohio (2.4%)       
Coshocton Cnty., Env. Rev. Bonds (Smurfit-Stone       
Container Corp.), 5 1/8s, 8/1/13  CCC+  600,000  596,016 
OH State Air Quality Dev. Auth. Rev. Bonds (Toledo       
Poll. Control), Ser. A, 6.1s, 8/1/27  Baa2  2,000,000  2,076,660 
Rickenbacker, Port Auth. Rev. Bonds (OASBO Expanded       
Asset Pooled), Ser. A, 5 3/8s, 1/1/32  A2  2,500,000  2,756,000 

Oklahoma (0.5%)       
OK Dev. Fin. Auth. Rev. Bonds (Hillcrest Hlth. Care       
Syst.), Ser. A, U.S. Govt. Coll., 5 5/8s, 8/15/29       
(Prerefunded)  Aaa  1,050,000  1,116,150 

Oregon (0.4%)       
OR State Hsg. & Cmnty. Svcs. Dept. Rev. Bonds (Single       
Family Mtge.), Ser. K, 5 5/8s, 7/1/29  Aa2  845,000  869,691 

Pennsylvania (5.9%)       
Bucks Cnty., Indl. Dev. Auth. Retirement Cmnty. Rev.       
Bonds (Ann's Choice, Inc.), Ser. A, 5.4s, 1/1/15  BB/P  530,000  538,957 
Carbon Cnty., Indl. Dev. Auth. Rev. Bonds (Panther       
Creek Partners), 6.65s, 5/1/10  BBB-  870,000  911,299 
Lancaster Cnty., Hosp. Auth. Rev. Bonds (Gen. Hosp.),       
5 1/2s, 3/15/26  A+  1,500,000  1,595,970 
Lehigh Cnty., Gen. Purpose Auth. Rev. Bonds (Lehigh       
Valley Hosp. Hlth. Network), Ser. A, 5 1/4s, 7/1/32  A1  1,000,000  1,043,150 
PA State Econ. Dev. Fin. Auth. Resource Recvy. Rev.       
Bonds (Northampton Generating), Ser. A, 6.6s, 1/1/19  B+  750,000  750,105 
PA State Higher Edl. Fac. Auth. Rev. Bonds       
(Philadelphia College of Osteopathic Med.), 5s, 12/1/08  A  1,045,000  1,070,906 
Philadelphia, Indl. Dev. Auth. VRDN (Fox Chase Cancer       
Ctr.), 3.52s, 7/1/10  P-1  1,000,000  1,000,000 
Philadelphia, School Dist. G.O. Bonds, Ser. D, FGIC,       
5s, 6/1/27  Aaa  5,000,000  5,268,300 
Sayre, Hlth. Care Fac. Auth. Rev. Bonds (Guthrie       
Hlth.), Ser. A, 5 7/8s, 12/1/31  A-  1,000,000  1,083,030 

Puerto Rico (3.0%)       
Cmnwlth. of PR, G.O. Bonds (Pub. Impt.), Ser. A,       
5 1/4s, 7/1/25  BBB  1,000,000  1,064,660 
Cmnwlth. of PR, Govt. Dev. Bank Rev. Bonds, Ser. AA,       
5s, 12/1/16  BBB  250,000  266,915 
Cmnwlth. of PR, Hwy. & Trans. Auth. Rev. Bonds, Ser.       
B, 6s, 7/1/39 (Prerefunded)  BBB+  5,000,000  5,479,250 

South Carolina (3.2%)       
Florence Cnty., Hosp. Rev. Bonds (McLeod Regl. Med.       
Ctr.), Ser. A, FSA, 5 1/4s, 11/1/23  Aaa  2,515,000  2,708,177 
Greenwood Cnty., Hosp. Rev. Bonds (Memorial Hosp.),       
5 1/2s, 10/1/26  A2  750,000  789,533 
SC Hosp. Auth. Rev. Bonds (Med. U.), Ser. A, 6 1/2s,       
8/15/32 (Prerefunded)  AAA  1,000,000  1,146,950 
SC Jobs Econ. Dev. Auth. Hosp. Fac. Rev. Bonds       
(Palmetto Hlth. Alliance), Ser. A, 7 3/8s, 12/15/21       
(Prerefunded)  BBB+/F  600,000  695,622 
SC Tobacco Settlement Rev. Mgt. Rev. Bonds, Ser. B,       
6 3/8s, 5/15/28  BBB  1,750,000  1,878,415 

South Dakota (1.0%)       
SD Edl. Enhancement Funding Corp. Rev. Bonds, Ser. B,       
6 1/2s, 6/1/32  BBB  2,000,000  2,186,920 

Tennessee (4.4%)       
Johnson City, Hlth. & Edl. Fac. Board Hosp. Rev. Bonds       
(Mountain States Hlth.), Ser. A, 7 1/2s, 7/1/25  BBB+  2,000,000  2,334,900 
(First Mtge. - Mountain States Hlth.), Ser. A, MBIA,       
6s, 7/1/21  Aaa  7,000,000  7,569,170 

Texas (9.2%)       
Alliance, Arpt. Auth. Rev. Bonds (Federal Express       
Corp.), 4.85s, 4/1/21  Baa2  1,750,000  1,761,935 
Columbus, Indpt. School Dist. G.O. Bonds, PSFG,       
5 1/8s, 8/15/29  Aaa  4,525,000  4,776,907 
Conroe, Indpt. School Dist. G.O. Bonds (School House),       
PSFG, 5s, 2/15/26  Aaa  2,905,000  3,035,144 
Gateway, Pub. Fac. Corp. Rev. Bonds (Stonegate Villas       
Apt.), FNMA Coll., 4.55s, 7/1/34  Aaa  750,000  773,865 
Harris Cnty., Hlth. Fac. Rev. Bonds (Memorial Hermann       
Hlth. Care), Ser. A, 6 3/8s, 6/1/29 (Prerefunded)  A+  1,500,000  1,687,440 
Montgomery Cnty., G.O. Bonds (Library), Ser. B, AMBAC,       
5s, 3/1/26  Aaa  1,335,000  1,388,160 
Sam Rayburn Muni. Pwr. Agcy. Rev. Bonds, 6s, 10/1/21  Baa2  1,500,000  1,589,700 
Snyder, Indpt. School Dist. G.O. Bonds (School Bldg.),       
5 1/4s, 2/15/24  AAA  1,215,000  1,313,828 
5 1/4s, 2/15/23  AAA  1,150,000  1,245,243 
Socorro, Indpt. School Dist. G.O. Bonds, PSFG, 5s,       
8/15/29  AAA  1,360,000  1,419,718 
Tomball, Hosp. Auth. Rev. Bonds (Tomball Regl. Hosp.),       
6s, 7/1/19  Baa3  1,700,000  1,781,685 

Utah (4.2%)       
Intermountain Pwr. Agcy. Rev. Bonds       
Ser. A, MBIA, 6.15s, 7/1/14  Aaa  70,000  71,512 
Ser. A, MBIA, U.S. Govt. Coll., 6.15s, 7/1/14       
(Prerefunded)  Aaa  8,280,000  8,603,996 
UT Cnty., Env. Impt. Rev. Bonds (Marathon Oil), 5.05s,       
11/1/17  Baa1  675,000  714,953 

Vermont (0.4%)       
VT Hsg. Fin. Agcy. Rev. Bonds, Ser. 19A, FSA, 4.62s,       
5/1/29  Aaa  915,000  924,013 

Virginia (0.9%)       
Prince William Cnty., Indl. Dev. Auth. Hosp. Rev.       
Bonds (Potomac Hosp. Corp.), 5.35s, 10/1/36  A3  2,000,000  2,116,220 

Washington (1.1%)       
Tobacco Settlement Auth. of WA Rev. Bonds, 6 1/2s,       
6/1/26  BBB  2,320,000  2,545,898 

West Virginia (6.3%)       
Econ. Dev. Auth. Lease Rev. Bonds (Correctional       
Juvenile Safety), Ser. A, MBIA, 5s, 6/1/29  Aaa  7,500,000  7,867,050 
West Virginia U. Rev. Bonds (Impt. West VA. U.), Ser.       
C, FGIC, 5s, 10/1/26  Aaa  6,000,000  6,304,500 

Wisconsin (3.8%)       
Badger Tobacco Settlement Asset Securitization Corp.       
Rev. Bonds       
7s, 6/1/28  BBB  1,800,000  1,999,188 
6 3/8s, 6/1/32  BBB  3,500,000  3,778,705 
WI State Hlth. & Edl. Fac. Auth. Rev. Bonds (Wheaton       
Franciscan), 5 3/4s, 8/15/30  A2  2,500,000  2,671,400 

Wyoming (1.0%)       
Sweetwater Cnty., Poll. Control VRDN (Pacificorp.),       
Ser. B, 3 1/2s, 1/1/14  P-1  2,275,000  2,275,000 

Total investments (cost $345,516,202) (b)      $362,088,224 

FUTURES CONTRACTS OUTSTANDING at 8/31/06 (Unaudited)         
  Number of    Expiration  Unrealized 
  contracts  Value  date  appreciation 

U.S. Treasury Note 10 yr (Long)  22  $2,362,250  Dec-06  $9,224 


(a) Percentages indicated are based on net assets of $225,210,562.

(RAT) The Moody's, Standard & Poor's or Fitch's ratings indicated are believed to be the most recent ratings available at August 31, 2006 for the securities listed. Ratings are generally ascribed to securities at the time of issuance. While the agencies may from time to time revise such ratings, they undertake no obligation to do so, and the ratings do not necessarily represent what the agencies would ascribe to these securities at August 31, 2006. Securities rated by Putnam are indicated by "/P". Securities rated by Fitch are indicated by "/F".

(b) The aggregate identified cost on a tax basis is $345,516,202, resulting in gross unrealized appreciation and depreciation of $17,106,140 and $534,118, respectively, or net unrealized appreciation of $16,572,022.

(SEG) A portion of this security was pledged and segregated with the custodian to cover margin requirements for futures contracts at August 31, 2006.

At August 31, 2006, liquid assets totaling $2,362,250 have been designated as collateral for open futures contracts.

144A after the name of an issuer represents securities exempt from registration under Rule 144A under the Securities Act of 1933, as amended. These securities may be resold in transactions exempt from registration, normally to qualified institutional buyers.

The rates shown on VRDN and Mandatory Put Bonds are the current interest rates at August 31, 2006.

The dates shown on Mandatory Put Bonds are the next mandatory put dates.

The dates shown on debt obligations other than Mandatory Put Bonds are the original maturity dates.

The fund had the following industry group concentrations greater than 10% at August 31, 2006 (as a percentage of net assets):  
Health care  39.2% 
Utilities and power  31.1 
Air transportation  10.0 
The fund had the following insurance concentrations greater than 10% at August 31, 2006 (as a percentage of net assets):   
AMBAC  21.9% 
MBIA  21.8 
FGIC  13.1 

Security valuation Tax-exempt bonds and notes are valued at fair value on the basis of valuations provided by an independent pricing service, approved by the Trustees. Such services use information with respect to transactions in bonds, quotations from bond dealers, market transactions in comparable securities and various relationships between securities in determining value. Other investments are valued at fair value following procedures approved by the Trustees. Such valuations and procedures are reviewed periodically by the Trustees. The fair value of securities is generally determined as the amount that the fund could reasonably expect to realize from an orderly disposition of such securities over a reasonable period of time. By its nature, a fair value price is a good faith estimate of the value of a security at a given point in time and does not reflect an actual market price, which may be different by a material amount.

Futures and options contracts The fund may use futures and options contracts to hedge against changes in the values of securities the fund owns or expects to purchase, or for other investment purposes. The fund may also write options on swaps or securities it owns or in which it may invest to increase its current returns.

The potential risk to the fund is that the change in value of futures and options contracts may not correspond to the change in value of the hedged instruments. In addition, losses may arise from changes in the value of the underlying instruments, if there is an illiquid secondary market for the contracts, or if the counterparty to the contract is unable to perform. Risks may exceed amounts recognized on the statement of assets and liabilities. When the contract is closed, the fund records a realized gain or loss equal to the difference between the value of the contract at the time it was opened and the value at the time it was closed. Realized gains and losses on purchased options are included in realized gains and losses on investment securities. If a written call option is exercised, the premium originally received is recorded as an addition to sales proceeds. If a written put option is exercised, the premium originally received is recorded as a reduction to the cost of investments.

Futures contracts are valued at the quoted daily settlement prices established by the exchange on which they trade. The fund and the broker agree to exchange an amount of cash equal to the daily fluctuation in the value of the futures contract. Such receipts or payments are known as “variation margin.” Exchange traded options are valued at the last sale price or, if no sales are reported, the last bid price for purchased options and the last ask price for written options. Options traded over-the-counter are valued using prices supplied by dealers. Futures and written option contracts outstanding at period end, if any, are listed after the fund’s portfolio.

For additional information regarding the fund please see the fund's most recent annual or semiannual shareholder report filed on the Securities and Exchange Commission's Web site, www.sec.gov, or visit Putnam's Individual Investor Web site at www.putnaminvestments.com

Item 2. Controls and Procedures:

(a) The registrant's principal executive officer and principal financial officer have concluded, based on their evaluation of the effectiveness of the design and operation of the registrant's disclosure controls and procedures as of a date within 90 days of the filing date of this report, that the design and operation of such procedures are generally effective to provide reasonable assurance that information required to be disclosed by the registrant in this report is recorded, processed, summarized and reported within the time periods specified in the Commission's rules and forms.

(b) Changes in internal control over financial reporting: Not applicable

Item 3. Exhibits:

Separate certifications for the principal executive officer and principal financial officer of the registrant as required by Rule 30a-2(a) under the Investment Company Act of 1940, as amended, are filed herewith.


Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

Putnam Investment Grade Municipal Trust

By (Signature and Title):

/s/ Michael T. Healy
Michael T. Healy
Principal Accounting Officer
Date: October 26, 2006

Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, this report has been signed below by the following persons on behalf of the registrant and in the capacities and on the dates indicated.

By (Signature and Title):

/s/ Charles E. Porter
Charles E. Porter
Principal Executive Officer
Date: October 26, 2006

By (Signature and Title):

/s/ Steven D. Krichmar
Steven D. Krichmar
Principal Financial Officer
Date: October 26, 2006