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:__811-21181______

_______BlackRock Municipal 2020 Term Trust_______
(Exact name of registrant as specified in charter)

100 Bellevue Parkway, Wilmington, DE
19809


(Address of principal executive offices)
(Zip code)

Robert S. Kapito, President

BlackRock Municipal 2020 Term Trust

      40 East 52nd Street, New York, NY 10022      
(Name and address of agent for service)


Registrant’s telephone number, including area code:_
888-825-2257__________________

Date of fiscal year end:___December 31, 2006
Date of reporting period:__
September 30, 2006


Item 1. Schedule of Investments.

The Registrant’s unaudited schedule of investments as of the close of the reporting period pursuant to Rule 30b1-5 under the Investment Company Act of 1940 is as follows:


PORTFOLIO OF INVESTMENTS (unaudited)
SEPTEMBER 30, 2006

BlackRock Municipal 2020 Term Trust (BKK)

Principal        
  Amount     Option Call  
Rating1 (000)   Description Provisions2 Value  







    LONG-TERM INVESTMENTS—153.2%    
      California—22.6%    
A+ $12,000   California GO, 5.00%, 11/01/22 11/13 @ 100 $ 12,604,440  
      Foothill/Eastern Corridor Agcy. Toll Rd. Cap. Apprec. RB,    
BBB 12,500       Zero Coupon, 1/15/21 01/10 @ 53.346 5,496,250  
BBB 10,000       Zero Coupon, 1/15/22 01/10 @ 50.177 4,136,800  
      Golden St. Tobacco Sec. Corp. RB,    
BBB 3,000       Ser. A-1, 6.625%, 6/01/40 06/13 @ 100 3,364,800  
BBB 12,010       Ser. A-1, 6.75%, 6/01/39 06/13 @ 100 13,556,047  
BBB 975       Ser. A-3, 7.875%, 6/01/42 06/13 @ 100 1,192,640  
BBB 1,470       Ser. A-5, 7.875%, 6/01/42 06/13 @ 100 1,798,133  
AAA 20,000 3     Ser. B, 5.375%, 6/01/10 N/A 21,248,000  
AAA 6,865   Riverside Cnty. RB, Riverside Cnty. Hosp. Proj., Zero Coupon, 6/01/25, MBIA No Opt. Call 2,906,435  
A+ 5,000   Statewide Cmntys. Dev. Auth. RB, John Muir Hlth. Proj., Ser. A, 5.00%, 8/15/22 08/16 @ 100 5,282,800  

          71,586,345  

      Colorado—1.7%    
AAA 4,500   E-470 Pub. Hwy. Auth. Cap. Apprec. RB, Ser. B, Zero Coupon, 9/01/22, MBIA No Opt. Call 2,210,085  
Baa2 3,000   Park Creek Met. Dist. RB, 5.25%, 12/01/25 12/15 @ 101 3,118,410  

          5,328,495  

      District of Columbia—5.1%    
      RB, Friendship Pub. Charter Sch., Inc. Proj.    
A 3,320       5.00%, 6/01/23, ACA 06/14 @ 100 3,385,371  
A 2,680       5.75%, 6/01/18, ACA 06/14 @ 100 2,911,069  
AAA 5,000   Met. Washington Arpts. Auth. Arpt. Sys. RB, Ser. C-2, 5.00%, 10/01/24, FSA, AMT 10/14 @ 100 5,244,950  
BBB 4,215   Tobacco Settlement Fin. Corp. Asset Bkd. RB, 6.50%, 5/15/33 No Opt. Call 4,919,874  

          16,461,264  

      Florida—14.8%    
NR 830   Baywinds Cmnty. Dev. Dist. SA, Ser. B, 4.90%, 5/01/12 No Opt. Call 837,985  
NR 4,690   Bellago Edl. Facs. Benefit Dist. SA, Ser. A, 5.85%, 5/01/22 05/14 @ 100 4,849,085  
Baa2 1,500   Cap. Trust Agcy. Multi-Fam. Hsg. RB, American Oppty. Proj., Ser. A, 5.75%, 6/01/23 06/13 @ 102 1,478,715  
NR 3,000   CFM Cmnty. Dev. Dist. Cap. Impvt. RB, Ser. B, 5.875%, 5/01/14 No Opt. Call 3,072,300  
NR 4,320   Grand Hampton Cmnty. Dev. Dist. Cap. Impvt. RB, 6.10%, 5/01/24 05/13 @ 101 4,533,321  
NR 4,025   Habitat Cmnty. Dev. Dist. SA, 5.80%, 5/01/25 05/14 @ 101 4,205,642  
BB+ 5,475   Miami Beach Hlth. Facs. Auth. RB, Mt. Sinai Med. Ctr. Proj., 6.75%, 11/15/21 11/14 @ 100 6,191,130  
NR 4,525   Middle Vlg. Cmnty. Dev. Dist. SA, Ser. A, 5.80%, 5/01/22 05/13 @ 100 4,696,226  
NR 1,000   Pine Islands Cmnty. Dev. Dist. Util. Sys. RB, 5.30%, 11/01/10 No Opt. Call 996,370  
NR 6,080   Stevens Plantation Cmnty. Dist. SA, Ser. B, 6.375%, 5/01/13 No Opt. Call 6,262,339  
NR 3,480   Vlg. Cmnty. Dev. Dist. No. 5 SA, Ser. A, 6.00%, 5/01/22 05/13 @ 101 3,677,107  
NR 5,810   Westchester Cmnty. Dev. Dist. No. 1 SA, 6.00%, 5/01/23 05/13 @ 101 6,165,398  

          46,965,618  

      Georgia—1.6%    
BBB 2,500   Milledgeville Baldwin Cnty. Dev. Auth. RB, Georgia Coll. & St. Univ. Fndtn. Proj.,    
          5.50%, 9/01/24 09/14 @ 101 2,672,575  
BBB 2,350   Richmond Cnty. Dev. Auth. Env. Impvt. RB, 5.75%, 11/01/27, AMT 11/13 @ 100 2,470,978  

          5,143,553  

      Illinois—12.5%    
NR 2,155 4 Centerpoint Intermodal Ctr. Prog. Trust TA, Ser. A, 8.00%, 6/15/23 No Opt. Call 2,209,414  
      Chicago O’Hare Intl. Arpt. RB,    
AAA 5,000       Ser. A, 5.00%, 1/01/21, AMBAC 01/16 @ 100 5,323,150  
AAA 7,000       Ser. A, 5.00%, 1/01/22, AMBAC 01/16 @ 100 7,441,350  
A- 5,000   Dev. Fin. Auth. RB, Depaul Univ. Proj., Ser. C, 5.25%, 10/01/24 10/14 @ 100 5,335,800  
AAA 4,800   Edl. Fac. Auth. RB, Northwestern Univ. Proj., 5.00%, 12/01/21 12/13 @ 100 5,077,584  
      Fin. Auth. Student Hsg. RB, MJH Ed. Asst. Living Proj.,    
Baa2 2,725       Ser. A, 5.00%, 6/01/24 06/14 @ 100 2,784,187  
Baa2 3,250       Ser. A, 5.50%, 6/01/19 06/14 @ 100 3,467,620  
Baa3 1,075       Ser. B, 5.00%, 6/01/24 06/14 @ 100 1,091,404  
AAA 13,455   Met. Pier & Expo. Auth. Ded. RB, McCormick Place Expansion Proj., Ser. A, Zero Coupon,    
          6/15/22, MBIA No Opt. Call 6,742,839  

          39,473,348  

1


BlackRock Municipal 2020 Term Trust (BKK) (continued)

    Principal            
      Amount       Option Call    
  Rating1   (000)   Description   Provisions2   Value  

        Indiana—5.0%        
  BBB   $10,000   Indianapolis Arpt. Auth. RB, FedEx Corp. Proj., 5.10%, 1/15/17, AMT   No Opt. Call   $ 10,590,200  
  NR   5,140   Vincennes Econ. Dev. RB, Southwest Indiana Regl. Youth Proj., 6.25%, 1/01/24   01/09 @ 102   5,134,089  

                  15,724,289  

          Kansas—1.1%        
  AAA   6,440   Wyandotte Cnty. Unified Gov’t. SO RB, Intl. Speedway Proj., Zero Coupon, 12/01/20, MBIA   No Opt. Call   3,420,220  

          Louisiana—0.7%        
  BBB   2,000   De Soto Parish Env. Impvt. RB, Ser. A, 5.85%, 11/01/27, AMT   11/13 @ 100   2,114,800  

          Maryland—5.5%        
          Frederick Cnty. ST, Urbana Cmnty. Dev. Auth. Proj.,        
  NR   3,000       6.625%, 7/01/25   07/07 @ 102   3,089,940  
  NR   5,171       Ser. A, 5.80%, 7/01/20   07/07 @ 102   5,258,080  
  BBB+   8,500   Hlth. & Higher Edl. Facs. Auth. RB, Medstar Hlth. Proj., 5.375%, 8/15/24   08/14 @ 100   9,057,090  

                  17,405,110  

          Massachusetts—1.5%        
  BBB   4,500   Dev. Fin. Agcy. Sld. Wst. Disp. RB, Wst. Mgmt., Inc. Proj., 5.45%, 6/01/14, AMT   No Opt. Call   4,792,050  

          Minnesota—0.4%        
  A2   1,250   Higher Ed. Facs. Auth. RB, Univ. of St. Thomas Proj., Ser. 5, 5.00%, 10/01/24   10/14 @ 100   1,316,425  

          Mississippi—1.0%        
  BBB   3,000   Warren Cnty. Env. Impvt. RB, Intl. Paper Proj., Ser. A, 5.85%, 11/01/27, AMT   11/13 @ 100   3,172,200  

          Missouri—3.5%        
  BBB+   5,000   Dev. Fin. Brd. RB, Branson Landing Proj., Ser. A, 5.50%, 12/01/24   06/14 @ 100   5,300,600  
  AA   5,500   Hlth. & Ed. Fac. Auth. RB, BJC Hlth. Sys. Proj., Ser. A, 5.00%, 5/15/20   05/15 @ 100   5,827,250  

                  11,127,850  

          Multi-State—7.3%        
          Charter Mac Equity Issuer Trust,        
  A3   1,000 4     Ser. A, 5.75%, 4/30/15   No Opt. Call   1,077,730  
  A3   2,500 4     Ser. A, 6.00%, 4/30/19   No Opt. Call   2,770,650  
  Baa1   4,000 4     Ser. B, 6.00%, 4/30/15   No Opt. Call   4,230,240  
  Baa1   2,500 4     Ser. B, 6.30%, 4/30/19   No Opt. Call   2,705,675  
          Munimae TE Bond Subsidiary, LLC,        
  Baa2   5,000 4     Ser. C1, 5.80%, 6/30/49   09/14 @ 100   5,100,650  
  Baa2   5,000 4     Ser. C2, 5.80%, 6/30/49   09/19 @ 100   5,086,750  
  Baa3   2,000 4     Ser. D, 5.90%, 9/15/49   09/15 @ 101   2,044,740  

                23,016,435  

          Nevada—2.2%        
  A+   5,000   Clark Cnty. Econ. Dev. RB, Alexander Dawson Sch. Proj., 5.00%, 5/15/20   05/16 @ 100   5,264,950  
  NR   1,765   Henderson Local Impvt. Dist. No. T18 SA, 5.15%, 9/01/21   03/07 @ 103   1,789,392  

                  7,054,342  

          New Hampshire—4.9%        
  Aaa   10,000   Bus. Fin. Auth. PCRB, Pub. Svc. Co. Proj., Ser. B, 4.75%, 5/01/21, MBIA, AMT   06/13 @ 102   10,265,000  
  A-   5,000   Hlth. & Ed. Fac. RB, Elliot Hosp. Proj., Ser. B, 5.60%, 10/01/22   10/13 @ 100   5,342,250  

                  15,607,250  

          New Jersey—11.7%        
          Econ. Dev. Auth. RB,        
  BBB   11,500       Cigarette Tax Proj., 5.50%, 6/15/24   06/12 @ 100   12,098,460  
  B   5,000       Continental Airlines, Inc. Proj., 7.00%, 11/15/30, AMT   11/10 @ 101   5,247,150  
  B   1,500       Continental Airlines, Inc. Proj., 9.00%, 6/01/33, AMT   06/13 @ 101   1,825,020  
  BBB-   1,000       First Mtg. Winchester Proj., Ser. A, 4.80%, 11/01/13   No Opt. Call   1,011,840  
  Baa3   7,500       Kapkowski Rd. Landfill Proj., 6.50%, 4/01/31, AMT   No Opt. Call   8,870,025  
  Baa1   4,000   Hlth. Care Fac. Fin. Auth. RB, Cap. Hlth. Sys. Oblig. Grp. Proj., Ser. A, 5.75%, 7/01/23   07/13 @ 100   4,316,600  
          Middlesex Cnty. Impvt. Auth. RB,        
  NR   2,500       Heldrich Ctr. Hotel Proj., Ser. B, 6.125%, 1/01/25   01/15 @ 100   2,580,725  
  Baa1   1,000       Str. Student Hsg. Proj., Ser. A, 5.00%, 8/15/23   08/14 @ 100   1,024,920  

                  36,974,740  

2


BlackRock Municipal 2020 Term Trust (BKK) (continued)

    Principal            
      Amount       Option Call    
  Rating1   (000)   Description   Provisions2   Value  

        New York—8.4%         
          New York City Indl. Dev. Agcy. RB, American Airlines, JFK Intl. Arpt. Proj.,        
  B   $ 5,635       7.625%, 8/01/25, AMT   08/16 @ 101   $6,618,871  
  B   5,000       7.75%, 8/01/31, AMT   08/16 @ 101   5,911,800  
  AAA   8,500   Energy Research & Dev. RB, Brooklyn Union Gas/Keyspan Proj., Ser. A, 4.70%,        
              2/01/24, FGIC, AMT   02/16 @ 100   8,666,770  
  AA-   5,000   Tobacco Settlement Fin. Corp. SA, Ser. B1, 5.50%, 6/01/20   06/13 @ 100   5,437,400  

                  26,634,841  

          Ohio—4.9%        
          Cuyahoga Cnty. RB, Cleveland Clinic Hlth. Sys. Proj.,        
  Aa3   3,000       6.00%, 1/01/19   07/13 @ 100   3,349,410  
  Aa3   10,000       6.00%, 1/01/20   07/13 @ 100   11,145,900  
  NR   1,100   Pinnacle Cmnty. Infrastructure Fin. Auth. Facs. RB, Ser. A, 6.00%, 12/01/22   12/14 @ 101   1,153,273  

                  15,648,583  

          Oklahoma—1.2%        
  B   3,350   Tulsa Mun. Arpt. Trust RB, Ser. A, 7.75%, 6/01/35, AMT   No Opt. Call   3,840,909  

          Pennsylvania—6.1%        
  BBB+   6,680   Higher Edl. Fac. RB, La Salle Univ. Proj., 5.50%, 5/01/26   05/13 @ 100   7,107,119  
  A+   10,000   Lancaster Cnty. Hosp. Auth. RB, Gen. Hosp. Proj., 5.75%, 3/15/20   09/13 @ 100   10,950,500  
  NR   1,275   Montgomery Cnty. Indl. Dev. Auth. RB, Whitemarsh Continuing Care Proj., 6.00%, 2/01/21   02/15 @ 100   1,351,424  

                  19,409,043  

          Puerto Rico—4.8%        
  BBB   3,300   Comnwlth. Pub. Impvt. GO, Ser. B, 5.25%, 7/01/17   07/16 @ 100   3,613,170  
  A3   10,900   Elec. Pwr. Auth. RB, Ser. NN, 5.125%, 7/01/24   07/13 @ 100   11,512,144  

                  15,125,314  

          Rhode Island—1.5%        
  Baa2   4,500 3 Hlth. & Edl. Bldg. Corp. Hosp. Fin. RB, Ser. A, 5.875%, 9/15/08   N/A   4,691,610  

          Tennessee—3.5%        
  AA-   10,000   Energy Aquisition Corp. RB, Ser. A, 5.25%, 9/01/20   No Opt. Call   11,119,500  

          Texas—5.9%        
  BBB   1,100   Brazos River Auth. PCRB, TXU Energy Co. LLC Proj., Ser. A, 6.75%, 4/01/38, AMT   No Opt. Call   1,241,185  
  BBB-   3,500   Port Corpus Christi Indl. Dev. Corp. RB, Valero Proj., Ser. C, 5.40%, 4/01/18   04/08 @ 102   3,638,845  
          Tpke. Auth. RB, Central Texas Tpke. Sys. Proj.,        
  AAA   7,990       Ser. A, Zero Coupon, 8/15/21, AMBAC   No Opt. Call   4,184,044  
  AAA   8,450       Ser. A, Zero Coupon, 8/15/24, AMBAC   No Opt. Call   3,802,669  
          Weatherford Indpt. Sch. Dist. GO,        
  AAA   6,945       Zero Coupon, 2/15/23, PSF   02/11 @ 50.236   2,916,344  
  AAA   6,945       Zero Coupon, 2/15/24, PSF   02/11 @ 47.435   2,750,220  

                  18,533,307  

          Trust Territories—1.3%        
  A   4,000 4 San Manuel Entertainment Auth. RB, 2004 Gaming Proj., Ser. C, 4.50%, 12/01/16   12/13 @ 102   4,028,680  

          U.S. Virgin Islands—0.3%        
  BBB   1,000   Pub. Fin. Auth. RB, Sen. Lien Matching Fund Loan, Ser. A, 5.25%, 10/01/17   10/14 @ 100   1,071,360  

          Virginia—7.5%        
  NR   5,000   Celebrate North Cmnty. Dev. Auth. SA, Ser. B, 6.60%, 3/01/25   03/14 @ 102   5,318,850  
  BBB   10,000   Charles City Cnty. Econ. Dev. Auth. Sld. Wst. Disp. RB, 5.125%, 8/01/27, AMT   09/06 @ 100   10,249,300  
  Baa1   7,500   Mecklenburg Cnty. Ind. Dev. Auth. RB, Exempt FAC-UAE LP Proj., 6.50%, 10/15/17, AMT   10/12 @ 100   8,280,225  

                  23,848,375  

          Washington—2.6%        
          Washington GO,        
  AAA   10,000       Ser. S-5, Zero Coupon, 1/01/19, FGIC   No Opt. Call   5,904,900  
  AAA   4,630       Mtr. Veh. Proj., Ser. F, Zero Coupon, 12/01/21, MBIA   No Opt. Call   2,379,496  

                  8,284,396  

          Wisconsin—2.1%        
          Hlth. & Ed. Fac. Auth. RB, Wheaton Franciscan Svcs. Proj.,        
  A   2,880       5.50%, 8/15/17   08/13 @ 100   3,093,984  
  A   3,190       5.50%, 8/15/18   08/13 @ 100   3,409,408  

                  6,503,392  

          Total Long-Term Investments (cost $455,264,924)       485,423,644  

3


BlackRock Municipal 2020 Term Trust (BKK) (continued)

Principal        
  Amount        
Rating1 (000)   Description   Value  

    SHORT-TERM INVESTMENTS—1.4%    
      New York—0.1%    
A-1+ $ 300 5 Triborough Brdg. & Tunl. Auth. RB, 3.71%, 10/05/06, FRWD N/A $ 300,000  

      Tennessee—0.6%    
VMIG1 1,800 5 Montgomery Cnty. Pub. Bldg. Auth. RB, 3.85%, 10/02/06, FRDD N/A 1,800,000  

 
Shares
       
 
(000)
       

      Money Market Fund—0.7%    
NR 2,350   AIM Tax Free Cash Reserve Portfolio N/A 2,350,000  

      Total Short-Term Investments (cost $4,450,000)   4,450,000  

      Total Investments—154.6% (cost $459,714,9246)   $ 489,873,644  
      Other assets in excess of liabilities—1.5%   4,601,813  
      Preferred shares at redemption value, including dividends payable—(56.1)%   (177,679,227)  

      Net Assets Applicable to Common Shareholders—100%   $ 316,796,230  


1 Using the highest of Standard & Poor’s, Moody’s Investmors Services or Fitch’s ratings.  
2 Date (month/year) and price of the earliest optional call or redemption. There may be other call provisions at varying prices at later dates.  
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 Security is not registered under the Securities Act of 1933. These securities may be resold in transactions in accordance with Rule 144A under that Act, to qualified institutional buyers. As of September 30, 2006, the Trust held 9.2% of its net assets, with a current market value of $29,254,529, in securities restricted as to resale.  
5 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, 2006.  
6 Cost for Federal income tax purposes is $459,687,475. The net unrealized appreciation on a tax basis is $30,186,169, consisting of $30,191,538 gross unrealized appreciation and $5,369 gross unrealized depreciation. 

KEY TO ABBREVIATIONS
 
ACA American Capital Access   MBIA Municipal Bond Insurance Assoc.  
AMBAC American Municipal Bond Assurance Corp.   PCRB Pollution Control Revenue Bond  
AMT Subject to Alternative Minimum Tax   PSF Public School Fund Guaranteed  
FGIC Financial Guaranty Insurance Co.   RB Revenue Bond  
FRDD Floating Rate Daily Demand   SA Special Assessment  
FRWD Floating Rate Weekly Demand   SO Special Obligation  
FSA Financial Security Assurance   ST Special Tax  
GO General Obligation   TA Tax Allocation  

4


Item 2. Controls and Procedures.

(a) The Registrant’s principal executive and principal financial officers have evaluated the Registrant’s disclosure controls and procedures within 90 days of this filing and have concluded, as of that date, that the Registrant’s disclosure controls and procedures were reasonably designed to ensure that information required to be disclosed by the Registrant in this Form N-Q was recorded, processed, summarized, and reported within the required time periods and that information to be disclosed by the Registrant in this Form N-Q was accumulated and communicated to the Registrant’s management, including its principal executive and principal financial officers, as appropriate, to allow timely decisions regarding required disclosure.

(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 (17 CFR 270.30a -3(d)) 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.

Separate certifications of the Registrant’s Principal Executive and Financial Officers pursuant to Section 302 of the Sarbanes-Oxley Act of 2002 are attached as EX-99.CERT.

 


SIGNATURES

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.

(Registrant)___BlackRock Municipal 2020 Term Trust___

By: /s/ Donald C. Burke
_____________________________________________________________________
Name: Donald C. Burke
Title: Treasurer and Principal Financial Officer
Date: November 29, 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: /s/ Robert S. Kapito
_____________________________________________________________________
Name: Robert S. Kapito
Title: President and Principal Executive Officer
Date: November 29, 2006

By: /s/ Donald C. Burke
_____________________________________________________________________
Name: Donald C. Burke
Title: Treasurer and Principal Financial Officer
Date: November 29, 2006