UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

FORM N-Q

QUARTERLY SCHEDULE OF PORTFOLIO HOLDINGS OF REGISTERED
MANAGEMENT INVESTMENT COMPANY

Investment Company Act file number 811-06721

Name of Fund: BlackRock Insured Municipal 2008 Term Trust, Inc. (BRM)

Fund Address: 100 Bellevue Parkway, Wilmington, DE 19809

Name and address of agent for service: Donald C. Burke, Chief Executive Officer, BlackRock Insured Municipal 2008 Term Trust, Inc., 800 Scudders Mill Road, Plainsboro, NJ, 08536. Mailing address: P.O. Box 9011, Princeton, NJ, 08543-9011

Registrant’s telephone number, including area code: (800) 882-0052, Option 4

Date of fiscal year end: 12/31/2007

Date of reporting period: 07/01/2007 – 09/30/2007

Item 1 – Schedule of Investments

PORTFOLIO OF INVESTMENTS (unaudited)
SEPTEMBER 30, 2007
 BlackRock Insured Municipal 2008 Term Trust (BRM) 
(Percentages shown are based on Net Assets)

Principal
           
Amount
               
(000)
  Description      
Value
 
      LONG-TERM INVESTMENTS—85.4%        
      Alabama—1.6%        
$ 6,555   Birmingham Jefferson Civic Ctr. Auth. ST,        
         Ser. A, 4.25%, 1/01/09, FSA   $ 6,616,289  
      Arizona—2.0%        
  4,000   Chandler, Ad Valorem Ppty. Tax GO, Zero        
         Coupon, 7/01/08, FGIC     3,892,640  
  4,200   Pima Cnty., Hwy. Impvts. Misc. RB,        
         4.125%, 7/01/09, FGIC     4,247,796  
            8,140,436  
      California—1.2%        
  5,000   Dept. of Wtr. Recs., Cash Flow Mgmt.        
         Elec., Pwr. & Lt. RB, Ser. A, 3.125%,        
         5/01/08, FSA     4,989,300  
      Colorado—2.6%        
  1,000   City of Thornton, Pub. Impvts. Lease        
         Approp. COP, Zero Coupon, 7/01/08,        
         AMBAC     995,290  
  1,000   Cnty. of El Paso, Correctional Fac. Impvts.        
     
   Lease Approp. COP, Detention Fac. Proj.,
       
         Ser. B, 3.20%, 12/01/08, AMBAC     994,770  
  2,000   E-470 Pub. Hwy. Auth., Hwy. Tolls RB,        
         Ser. B, Zero Coupon, 9/01/11, MBIA     1,725,300  
  6,965   Regl. Transp. Dist., Trans. Impvts. Lease        
     
   Approp. COP, Trans. Vehicles Proj., Ser.
       
         A, 5.00%, 6/01/08, MBIA     7,030,958  
            10,746,318  
      Delaware—0.2%        
  650   Delaware River & Bay Auth., Pub. Impvts.        
     
   Port, Arpt. & Marina RB, 3.25%, 1/01/09,
       
         MBIA     647,517  
      District of Columbia—3.1%        
      Dist. of Columbia, Ad Valorem Ppty. Tax        
      GO,        
  195 1    Ser. B, 5.50%, 6/01/09, FSA     201,355  
  2,605      Ser. B, 5.50%, 6/01/09, FSA     2,689,767  
  10,000      Ser. B-1, 5.50%, 6/01/08, AMBAC     10,134,400  
            13,025,522  
      Florida—1.4%        
  2,280   Broward Cnty. Sch. Brd., Sch. Impvts.        
         Lease Renewal COP, Ser. B, 4.25%,        
         7/01/09, FSA     2,306,859  
  2,080   City of Tampa, Wtr. RB, Wtr. & Swr. Proj.,        
         5.50%, 10/01/08, FSA     2,121,683  
  1,300   Town of Palm Beach, Misc. RB, Beach        
     
   Restoration Proj., Ser. A, 5.00%, 1/01/09,
       
         FSA     1,324,375  
            5,752,917  
      Georgia—6.1%        
  5,000   Georgia GO, Ser. E, 5.25%, 2/01/10     5,198,250  
  20,000 2 Monroe Cnty. Dev. Auth., Indl. RB, Georgia        
         Pwr. Co. Plant Scherer Proj., 4.20%,        
         1/01/12, AMBAC     20,156,600  
            25,354,850  
      Hawaii—2.7%        
  4,750   City & Cnty. of Honolulu, Ad Valorem        
         Ppty. Tax GO, Ser. E, 4.00%, 7/01/08,        
         FGIC     4,769,522  
  6,510   Hawaii GO, Ser. CY, 4.00%, 2/01/09, FSA     6,555,440  
            11,324,962  
Principal
           
Amount
               
(000)
  Description      
Value
 
      Illinois—11.4%        
      Cook Cnty. High Sch. Dist. No. 201, Cash        
      Flow Mgmt. Ad Valorem Ppty. Tax GO, J.        
      Sterling Morton Twnshp. Proj.,        
$
4,805
     Zero Coupon, 12/01/09, FGIC   $ 4,431,988  
 
1,175
 1    Zero Coupon, 12/01/09, FGIC     1,084,255  
 
2,000
  Cook Cnty. Sch. Dist. No. 25, Ad Valorem        
         Ppty. Tax GO, Arlington Heights Proj.,        
         4.50%, 12/01/08, FSA     2,023,900  
 
8,985
  Du Page Cnty. Forest Presvtn. Dist., Pub.        
     
   Impvts. Ad Valorem Ppty. Tax GO, Zero
       
         Coupon, 11/01/08     8,636,472  
 
13,000
 2 Fin. Auth. RB, Peoples Gas, Lt. & Coke        
         Proj., 3.05%, 2/01/33, AMBAC     12,966,720  
 
1,455
  Kane & Du Page Cntys. Cmnty. Unit Sch.        
 
     Dist. No. 303, Sch. Impvts. Ad Valorem        
 
     Ppty. Tax GO, Ser. A, 3.75%, 1/01/09,        
 
     FSA     1,459,743  
 
  Met. Pier & Expo. Auth.,        
 
8,385
 1    Pub. Impvts. Misc. Tax RB, McCormick        
 
     Place Expansion Proj., Zero Coupon,        
 
     6/15/08, FGIC     8,171,937  
 
215
     Pub. Impvts. Misc. Tax RB, McCormick        
 
     Place Expansion Proj., Zero Coupon,        
 
     6/15/08, FGIC     209,651  
 
1,570
 1    Student Loans Lease Abatement RB,        
 
     McCormick Place Expansion Proj., Ser.        
 
     A, Zero Coupon, 6/15/08, FGIC     1,530,106  
 
6,750
  Pub. Impvts. GO, Ser. 1, 3.50%, 7/01/08,        
 
     MBIA     6,751,755  
 
        47,266,527  
 
  Kansas—0.2%        
 
1,000
  Dev. Fin. Auth., Wtr. Util. Impvts. Wtr. RB,        
 
     4.00%, 4/01/09, AMBAC     1,008,010  
 
  Kentucky—0.9%        
 
3,890
  Owensboro, Elec., Pwr. & Lt. Impvts. RB,        
 
     Ser. B, Zero Coupon, 1/01/09, AMBAC     3,713,705  
 
  Michigan—2.8%        
 
6,315
  Detroit City Sch. Dist., Sch. Impvts. Ad        
     
   Valorem Ppty. Tax GO, Sch. Bldg. & Site
       
 
     Impvt. Proj., Ser. A, 4.00%, 5/01/09,        
 
     FGIC     6,366,214  
 
1,665
 1 Detroit, Pub. Impvts. Ad Valorem Ppty. Tax        
 
     GO, 3.50%, 4/01/09, MBIA     1,663,302  
 
3,000
  Michigan, Hwy. Impvts. Misc. RB, Trunk        
 
     Line Proj., Ser. A, 4.125%, 11/01/08, FSA     3,021,750  
 
765
  Wyandotte, Elec., Pwr. & Lt. RB, 6.25%,        
 
     10/01/08, MBIA     773,400  
 
        11,824,666  
 
  Mississippi—0.5%        
 
2,175
  De Soto Cnty. Sch. Dist., Ad Valorem Ppty.        
 
     Tax GO, 3.25%, 2/01/09, FSA     2,164,756  
 
  Nevada—1.3%        
 
  Director of the St. of Nevada Dept. of Bus.        
 
  & Ind., Trans. Impvts. RB, Las Vegas        
 
  Monorail Co. Proj.,        
 
2,085
     Zero Coupon, 1/01/09, AMBAC     1,989,528  
 
3,585
     Zero Coupon, 1/01/10, AMBAC     3,293,575  
 
        5,283,103  
 
  New Jersey—0.7%        
 
1,000
  Monmouth Cnty. Impvt. Auth., Misc. RB,        
         Gov't. Loan Proj., 5.00%, 12/01/08, FSA     1,017,880  


1

 BlackRock Insured Municipal 2008 Term Trust (BRM) (continued) 
(Percentages shown are based on Net Assets)

Principal
           
Amount
               
(000)
  Description      
Value
 
      New Jersey— (cont'd)        
$ 1,750   Transp. Trust Fund Auth., Trans. Impvts.        
         RB, Ser. C, 5.25%, 12/15/08, AMBAC   $ 1,787,240  
            2,805,120  
      New Mexico—0.6%        
  2,445   Fin. Auth., Pub. Impvt. Misc. RB, Ser. A,        
         3.80%, 6/01/08, MBIA     2,450,892  
      New York—4.9%        
  15,915   New York GO, Ser. F, 5.25%, 9/15/09,        
         MBIA     16,324,334  
  4,000   Port Auth. of New York & New Jersey,        
         Port, Arpt. & Marina RB, Ser. 129,        
         2.875%, 11/01/08, FSA     3,963,440  
            20,287,774  
      North Carolina—4.6%        
      Eastn. Mun. Pwr. Agcy., Elec., Pwr. & Lt.        
      RB,        
  13,500      Ser. B, 6.125%, 1/01/09, FGIC     13,921,605  
  5,000      Ser. B, 7.00%, 1/01/08, CAPMAC     5,042,850  
            18,964,455  
      Oregon—1.5%        
  2,905   Dept. of Admin. Svcs., Lease Approp. COP,        
         Ser. A, 5.00%, 11/01/08, FSA     2,951,190  
  1,285   Lane Cnty. Sch. Dist. No. 4-J, Ad Valorem        
         Ppty. Tax GO, Eugene Proj., 3.00%,        
         1/01/09, FSA     1,273,833  
  2,000   Washington & Clackamas Cntys. Sch. Dist.        
     
   No. 23-J, Sch. Impvts. Ad Valorem Ppty.
       
         Tax GO, Tigard Proj., 3.75%, 6/15/08,        
         MBIA     2,004,540  
            6,229,563  
      Pennsylvania—7.2%        
  3,175   City of Philadelphia, Pub. Impvts. Ad        
         Valorem Ppty. Tax GO, 4.10%, 9/15/08,        
         FSA     3,194,367  
  965 1 Dauphin Cnty. Gen. Auth., Hlth., Hosp. &        
     
   Nursing Home RB, Western Pennsylvania
       
         Hosp. Proj., Ser. B, 6.25%, 7/01/08,        
         MBIA     980,623  
      Dept. of Gen. Svcs., Lease Approp. COP,        
  2,075      4.50%, 5/01/08, FSA     2,086,745  
  2,120      4.50%, 11/01/08, FSA     2,142,006  
  2,165      4.50%, 5/01/09, FSA     2,196,826  
  16,250   Lehigh Cnty. Indl. Dev. Auth., Indl. RB,        
         PPL Elec. Util. Corp. Proj., 3.125%,        
         11/01/08, AMBAC     16,159,975  
  3,125   Pittsburgh Pub. Pkg. Auth., Auto Pkg. RB,        
         3.25%, 12/01/08, AMBAC     3,112,781  
            29,873,323  
      Tennessee—0.2%        
  1,000   Clarksville, Wtr. RB, 4.30%, 2/01/09, FSA     1,011,010  
      Texas—20.4%        
      City of Austin,        
  5,000      Elec., Pwr. & Lt. RB, 6.625%, 11/15/08,        
         AMBAC     5,170,350  
  5,000      Elec., Pwr. & Lt. RB, Ser. A, Zero        
         Coupon, 11/15/09, AMBAC     4,621,400  
  5,380      Pub. Impvts. Ad Valorem Ppty. Tax GO,        
         3.50%, 9/01/08, FSA     5,382,313  
  11,515      Wtr. RB, Ser. A, Zero Coupon, 11/15/08,        
         MBIA     11,051,176  
  5,000      Wtr. RB, Ser. A, Zero Coupon, 11/15/09,        
         MBIA     4,621,400  
  6,000 1 City of San Antonio, Elec., Pwr. & Lt. RB,        
         Ser. B, Zero Coupon, 2/01/10, FGIC     5,496,300  
Principal
           
Amount
           
(000)
      Description     
Value
 
      Texas— (cont'd)        
$ 1,430 1 Coppell Indpt. Sch. Dist., Ad Valorem Ppty.        
         Tax GO, 6.10%, 8/15/09, MBIA   $ 1,496,767  
  4,390   Houston Indpt. Sch. Dist., Ad Valorem Ppty.        
         Tax GO, Zero Coupon, 8/15/09, AMBAC     4,095,255  
      Mun. Pwr. Agcy., Elec., Pwr. & Lt. RB,        
  1,115 1    Zero Coupon, 9/01/08, AMBAC     1,078,316  
  13,885      Zero Coupon, 9/01/08, AMBAC     13,428,183  
  1,200 1    Zero Coupon, 9/01/09, AMBAC     1,117,812  
  14,975      Zero Coupon, 9/01/09, AMBAC     13,946,667  
  1,500   North Texas Tollway Auth., Hwy. Tolls RB,        
         Ser. C, 5.00%, 1/01/09, FSA     1,527,570  
      Pub. Fin. Auth.,        
  5,900      Lease Approp. RB, Ser. B, 6.25%,        
         2/01/09, AMBAC     6,108,919  
  750 3    Lease RB, Gen. Svcs. Comm. Projs.,        
         5.50%, 2/01/08, AMBAC     762,218  
  2,250      Lease RB, Gen. Svcs. Comm. Projs.,        
         5.50%, 2/01/09, AMBAC     2,287,215  
  2,275   Ysleta Indpt. Sch. Dist., Ad Valorem Ppty.        
         Tax GO, Zero Coupon, 8/15/08, PSF     2,203,770  
            84,395,631  
      Washington—6.6%        
  5,710   City of Seattle, Pub. Impvts. Ad Valorem        
         Ppty. Tax GO, 4.00%, 7/01/08, FSA     5,732,612  
  1,250   Clark Cnty. Pub. Util. Dist. No. 1, Elec.,        
         Pwr. & Lt. RB, 5.00%, 1/01/09, MBIA     1,273,125  
      Cnty. of King,        
  3,060      Ad Valorem Ppty. Tax GO, 3.50%,        
         12/01/08, FSA     3,060,581  
  12,850      Recreational Fac. Impvts. Ad Valorem        
         Ppty. Tax GO, Ser. D, 5.55%, 12/01/08,        
         MBIA     13,141,053  
  2,000   Energy Northwest, Elec., Pwr. & Lt. RB,        
         Pub. Pwr. No. 3 Proj., Ser. A, 5.40%,        
         7/01/08, MBIA     1,946,320  
      Hlth. Care Facs. Auth., Hlth., Hosp. &        
      Nursing Home Impvts. RB, Catholic Hlth.        
      Initiatives Proj.,        
  1,010      Ser. A, 5.30%, 12/01/08, MBIA     1,030,816  
  1,000      Ser. A, 5.40%, 12/01/10, MBIA     1,054,110  
            27,238,617  
      West Virginia—0.4%        
  1,550   Econ. Dev. Auth., Correctional Fac. Impvts.        
     
   Lease Approp. RB, Correctional Juvenile
       
         & Pub. Proj., Ser. A, 4.25%, 6/01/08,        
         MBIA     1,558,246  
      Wyoming—0.3%        
  1,270   Albany Cnty. Impvts. Stat. Trust, Pub.        
         Impvts. Lease Abatement COP, 3.75%,        
         1/15/09, MBIA     1,273,137  
      Total Long-Term Investments        
      (cost $348,011,445)     353,946,646  
     
SHORT-TERM INVESTMENTS—14.2%
       
      Alabama—0.7%        
  2,700 4 Southeast Gas Dist., Nat. Gas Util. Impvts.        
         RB, Ser. A, 4.11%, 10/01/07, FRDD     2,700,000  
      California—1.9%        
  2,915 4 Hlth. Facs. Fing. Auth., Hlth., Hosp. &        
         Nursing Home RB, Adventist Hlth. Sys.        
         Proj., Ser. B, 3.88%, 10/01/07, MBIA,        
         FRDD     2,915,000  


2

 BlackRock Insured Municipal 2008 Term Trust (BRM) (continued) 
(Percentages shown are based on Net Assets)

Principal
           
Amount
                 
(000)
  Description    
Value
 
      California— (cont'd)        
      Infrastructure & Econ. Dev. Bank,        
$ 595 4    Indl. Impvts. RB, Rand Corp. Proj., Ser.        
         B, 3.84%, 10/01/07, AMBAC, FRDD  
$
595,000  
  4,350 4    Indl. RB, San Fransico Ballet Assoc.        
         Proj., 3.86%, 10/01/07, FGIC, FRDD     4,350,000  
            7,860,000  
      Florida—0.6%        
  2,300 4 Pinellas Cnty. Hlth. Fac. Auth., Hlth., Hosp.        
         & Nursing Home RB, All Children's        
         Hosp. Proj., 4.03%, 10/01/07, AMBAC,        
         FRDD     2,300,000  
      Illinois—2.5%        
  4,150 4 Brd. of Ed., Sch. Impvts. Ad Valorem Ppty.        
         Tax GO, 4.05%, 10/01/07, CIFG, FRDD     4,150,000  
  6,250 4 Hlth. Facs Auth., Hlth., Hosp. & Nursing        
     
   Home RB, Univ. of Chicago Hosps. Proj.,
       
         4.00%, 10/01/07, MBIA, FRDD     6,250,000  
            10,400,000  
      Massachusetts—1.2%        
  5,000 4 Hlth. & Edl. Facs. Auth., Hlth., Hosp. &        
     
   Nursing Home RB, Childrens Hosp. Corp.
       
         Proj., Ser. L-2, 4.05%, 10/01/07,        
         AMBAC, FRDD     5,000,000  
      Michigan—4.1%        
      Hosp. Fin. Auth., Hlth., Hosp. & Nursing        
      Home Impvts. RB, Trinity Hlth. Proj.,        
  6,200 4    4.07%, 10/01/07, FRDD     6,200,000  
  11,000 4    Ser. E, 3.90%, 10/04/07, FRWD     11,000,000  
            17,200,000  
      Missouri—0.2%        
  705 4 Hlth. & Edl. Facs. Auth., Univ. & Coll.        
     
   Impvts. RB, Saint Louis Univ. Proj., Ser.
       
         A, 4.01%, 10/01/07, MBIA, FRDD     705,000  
      Oklahoma—0.6%        
  2,335 4 Tpke. Auth., Hwy. Tolls RB, Ser. D, 3.80%,        
         10/04/07, XLCA, FRWD     2,335,000  
      Pennsylvania—1.5%        
  2,200 4 Erie Wtr. Auth., Wtr. RB, Ser. A, 3.85%,        
         10/04/07, FSA, FRWD     2,200,000  
  4,090 4 Southcentral Gen. Auth., Hlth., Hosp. &        
     
   Nursing Home RB, Wellspan Hlth. Proj.,
       
         3.86%, 10/03/07, AMBAC, FRWD     4,090,000  
            6,290,000  
      Texas—0.9%        
  3,800 4 Harris Cnty. Hlth. Facs. Dev. Corp., Hlth.,        
     
   Hosp. & Nursing Home RB, Saint Luke’s
       
         Episcopal Hosp. Proj., 4.04%, 10/01/07,        
         FRDD     3,800,000  
      Total Short-Term Investments        
      (cost $58,590,000)     58,590,000  
Total Investments —99.6% (cost $406,601,4455)  
$
412,536,646  
Other assets in excess of liabilities —0.4%     1,808,231  
Net Assets —100%  
$
414,344,877  
 
 
 

 
1     

Security is collateralized by Municipal or U.S. Treasury obligations.
 
2

Variable rate security. Rate shown is interest rate as of September 30, 2007.
 
3

This bond is prerefunded. U.S. government securities, held in escrow, are used to pay interest on this security, as well as retire the bond in full at the date indicated, typically at a premium to par.
 
4

For purposes of amortized cost valuation, the maturity date of this instrument is considered to be the earlier of the next date on which the security can be redeemed at par, or the next date on which the rate of interest is adjusted. Rate shown is rate as of September 30, 2007.
 
5

Cost for federal income tax purposes is $406,087,280. The net unrealized appreciation on a tax basis is $6,449,366, consisting of $6,741,994 gross unrealized appreciation and $292,628 gross unrealized depreciation.
 
 

The value (market value plus accrued interest) of securities that are covered by insurance, which ensures the payment of principal and interest, represent approximately 91.3% of the Trust's net assets.
 
AMBAC   
— 34.3%
CAPMAC  
— 1.2%
CIFG  
— 1.0%
FGIC  
— 14.2%
FSA  
— 17.9%
MBIA  
— 21.6%
PSF  
— 0.5%
XCLA
  
— 0.6%

  KEY TO ABBREVIATIONS
AMBAC
   — American Municipal Bond Assurance Corp.
CAPMAC
  
— Capital Markets Assurance Co.
CIFG
   — CDC IXIS Financial Guaranty
COP
   — Certificate of Participation
FGIC
   — Financial Guaranty Insurance Co.
FRDD
   — Floating Rate Daily Demand
FRWD
   — Floating Rate Weekly Demand
FSA
   — Financial Security Assurance
GO
   — General Obligation
MBIA
   — Municipal Bond Insurance Assoc.
PCRB
   — Pollution Control Revenue Bond
PSF
   — Public School Fund Guaranteed
RB
   — Revenue Bond
ST
   — Special Tax
XLCA
   — XL Capital Assurance


 

3

Item 2 – Controls and Procedures
 
2(a) – The registrant’s principal executive and principal financial officers or persons performing similar functions have concluded that the registrant’s disclosure controls and procedures (as defined in Rule 30a-3(c) under the Investment Company Act of 1940, as amended (the “1940 Act”)) are effective as of a date within 90 days of the filing of this report based on the evaluation of these controls and procedures required by Rule 30a-3(b) under the 1940 Act and Rule 13a-15(b) under the Securities and Exchange Act of 1934, as amended.
 
2(b) – There were no changes in the registrant’s internal control over financial reporting (as defined in Rule 30a- 3(d) under the 1940 Act) that occurred during the registrant’s last fiscal quarter that have materially affected, or are reasonably likely to materially affect, the registrant’s internal control over financial reporting.
 
Item 3 – Exhibits

Certifications – Attached hereto

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.

BlackRock Insured Municipal 2008 Term Trust, Inc.

By:   /s/ Donald C. Burke
    Donald C. Burke,
    President & Chief Executive Officer of
    BlackRock Insured Municipal 2008 Term Trust, Inc.

Date: November 20, 2007

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:   /s/ Donald C. Burke
    Donald C. Burke,
    President & Chief Executive Officer (principal executive officer) of
    BlackRock Insured Municipal 2008 Term Trust, Inc.

Date: November 20, 2007

By:   /s/ Neal J. Andrews
    Neal J. Andrews,
    Chief Financial Officer (principal financial officer) of
    BlackRock Insured Municipal 2008 Term Trust, Inc.

Date: November 20, 2007