N-CSR

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM N-CSR

CERTIFIED SHAREHOLDER REPORT OF REGISTERED

MANAGEMENT INVESTMENT COMPANIES

Investment Company Act file number                                          811-02338                                                             

Allmerica Securities Trust

(Name of Registrant)

440 Lincoln Street

Worcester, Massachusetts 01653

(Address of principal executive offices) (Zip code)

George M. Boyd, Secretary

Allmerica Financial

440 Lincoln Street

Worcester, MA 01653

(Name and address of agent for service)

Registrant’s telephone number, including area code:  (508) 855-1000                                             

Date of fiscal year end: December 31                                                     

Date of reporting period: December 31, 2003                                        

Item 1. Reports to Stockholders

The following is a copy of the report transmitted to stockholders pursuant to Rule 30e-1 under the Investment Company Act of 1940:

Allmerica Securities Trust

Annual Report

December 31, 2003

Allmerica Financial

December 31, 2003

[GRAPHIC]

Annual Report

·    Allmerica Securities Trust

[GRAPHIC]

[GRAPHIC]

Table of Contents

Trust Information	2
A Letter from the Chairman	3
Trust Overview	4
Financials	F-1
Regulatory Disclosures and Shareholder Information	F-15

Trust Information

Board of Trustees

John P. Kavanaugh, Chairman

P. Kevin Condron*

Jocelyn S. Davis*

Cynthia A. Hargadon*

T. Britton Harris, IV*

Gordon Holmes*

Mark A. Hug

Attiat F. Ott*

Ranne P. Warner*

Officers

John P. Kavanaugh, President

Richard J. Litchfield, Vice President

Ann K. Tripp, Vice President

Donald P. Wayman, Vice President

Paul T. Kane, Treasurer

George M. Boyd, Secretary

Investment Manager

Opus Investment Management, Inc.

440 Lincoln Street, Worcester, MA 01653

Registrar and Transfer, Dividend Disbursing and Reinvestment Agent

The Bank of New York

P.O. Box 11258

Church Street Station, New York, NY 10286

Administrator and Custodian

Investors Bank & Trust Company

200 Clarendon Street, Boston, MA 02116

*Independent Trustees

Independent Accountants

PricewaterhouseCoopers LLP

160 Federal Street, Boston, MA 02110

Legal Counsel

Ropes & Gray LLP

One International Place, Boston, MA 02110

Shareholder Inquiries May Be Directed To:

The Bank of New York Shareholder Relations Dept.-11E

P.O. Box 11258

Church Street Station, New York, NY 10286

1-800-432-8224

2

A Letter from the Chairman

Dear Client:

We will remember 2003 as a year of broad-based economic recovery and above average investment returns across nearly all asset classes. Outside the United States, economic growth was tempered by growing worries over the decline in value of the U.S. dollar and concern that this could constrain the emerging global recovery. Still, stock markets around the world generally performed well. Japan’s Nikkei Average finished the period up 24.45%, Hong Kong’s Hang Seng Index was higher by 34.92%, Germany’s DAX Index rose 37.08%, England’s FTSE Index gained 13.62% and France’s CAC 40 Index was up 16.12%.

The United States economy displayed impressive strength in 2003. Early in the year, growth was hindered by major fighting in Iraq, a sluggish manufacturing sector and a lack of capital spending by businesses. The Federal Reserve Board cut the target federal funds rate to 1.00% and Congress passed a large tax cut, setting the stage for a rebound in economic activity. During the second half of the year, GDP rose sharply, productivity increased, corporate profits jumped, manufacturing gained strength and unemployment edged down. The consumer remained the primary source of spending, and business investment finally emerged. A full year of solid GDP growth provided the most compelling evidence yet that the growth engine of the world was back on track. U.S. securities markets reacted enthusiastically to the strong economic news. For the year, the S&P 500^® Index gained 28.69% and the Nasdaq Composite Index rose 50.01%. Bonds also generated positive returns for the year, evidenced by the Lehman Brothers Aggregate Bond Index, which increased 4.11%.

During this period of historically low interest rates, the Allmerica Securities Trust portfolio generated income supporting aggregate dividends of 56.5 cents per share in 2003. This translated to an annualized dividend yield of 5.79%, based on Allmerica Securities Trust’s December 31, 2003 closing price of $9.75 per share.

On behalf of the Board of Trustees,

John P. Kavanaugh

Chairman of the Board

Allmerica Securities Trust

3

Allmerica Securities Trust

The Allmerica Securities Trust returned 6.15% for 2003, underperforming its benchmark, the Lehman Brothers U.S. Credit Index, which returned 7.70%.

The Trust’s investment focus was turned toward providing stable income despite a historically low interest rate and spread environment. Throughout the year, as the economy and credit fundamentals continued to improve, the investment manager added more exposure to the “Baa” and “Ba” sectors, in order to add yield. The Trust remained overweight in the more conservative sectors, such as consumer non-cyclical, banking and finance, although more consumer cyclical names were introduced as the year progressed. The Trust’s underperformance was a result of the portfolio generally being positioned higher in quality relative to the benchmark, as a defensive posture. The underweight in the riskier names hurt performance. The lower quality sectors, in particular “Baa”, significantly outperformed the higher quality sectors.

The investment manager feels that economic growth will start strongly in 2004, as both the corporate sector and consumers appear ready to spend. The Federal Reserve Board has conveyed its inclination to keep interest rates steady, as long as inflation remains contained and slack remains in the labor and manufacturing segments. The investment manager believes that the Federal Reserve Board may raise interest rates in the mid to latter half of 2004 and that interest rates may be pressured up modestly as economic growth accelerates and the risk of inflation increases.

The investment manager thinks that geopolitical risk, terrorism risk, and dollar risk could alter this outlook. Should the dollar begin to free-fall, U.S. interest rates may be forced up dramatically, causing stock prices to drop, eroding consumer confidence and squashing capital spending.

Average Annual Total Returns

	1 Year		5 Year		10 Year
Allmerica Securities Trust	6.15	%	4.29	%	6.15	%
Lehman Brothers U.S. Credit Index	7.70	%	7.11	%	7.42	%
Lipper Corporate Debt Funds BBB-Rated Average	8.23	%	6.11	%	6.49	%

Historical Performance

	Total Return on Net Asset Value	Total Return on Market Value
1999	(1.42)%	(13.75)%
2000	6.76%	23.76%
2001	4.41%	6.00%
2002	5.54%	2.11%
2003	6.15%	9.38%

The Lehman Brothers U.S. Credit Index is an unmanaged index of all publicly issued, fixed-rate, non-convertible investment grade corporate debt. The Lipper Corporate Debt Funds BBB-Rated Average is a non-weighted index of funds within the Corporate Debt Funds BBB-Rated category.

Portfolio composition is subject to change.

Investment Manager

Opus Investment Management, Inc.

About the Trust

Seeks to generate a high rate of current income for distribution to shareholders.

Portfolio Composition

As of December 31, 2003, the sector allocation of net assets was:

4

Financials

[THIS PAGE INTENTIONALLY LEFT BLANK]

ALLMERICA SECURITIES TRUST

PORTFOLIO OF INVESTMENTS • December 31, 2003

Par Value		Moody’s Ratings (Unaudited)	Value (Note 2)
U.S. GOVERNMENT AGENCY MORTGAGE-BACKED OBLIGATIONS (h) - 0.4%
	Freddie Mac - 0.4%
$   154,899	5.00%, 05/15/21	NR	$	159,648
189,393	6.00%, 10/15/07	NR		198,724
				358,372
	Total U.S. Government Agency
	Mortgage-Backed Obligations			358,372
	(Cost $ 357,828)
U.S. GOVERNMENT AND AGENCY OBLIGATIONS - 2.8%
	Fannie Mae - 1.2%
275,000	3.70%, 11/01/07	Aaa		279,512
850,000	4.63%, 05/01/13	Aa2		827,232
				1,106,744
	Federal Home Loan Bank - 0.6%
550,000	2.25%, 05/15/06	Aaa		550,124
	U.S. Treasury Bond - 1.0%
120,000	5.25%, 02/15/29	NR		121,059
225,000	6.00%, 02/15/26	NR		249,513
450,000	6.25%, 05/15/30	NR		519,293
				889,865
	Total U.S. Government and
	Agency Obligations			2,546,733
	(Cost $ 2,590,464)
CORPORATE NOTES AND BONDS - 76.3%
	Aerospace & Defense - 1.1%
450,000	Northrop Grumman Corp.
	7.13%, 02/15/11	Baa3		520,464
450,000	Raytheon Co.
	5.38%, 04/01/13	Baa3		450,772
				971,236
	Automotive - 2.4%
460,000	DaimlerChrysler North America
	Holding Corp.
	6.90%, 09/01/04	A3		474,523
500,000	DaimlerChrysler North America
	Holding Corp.
	8.50%, 01/18/31	A3		597,392
500,000	General Motors Corp. (a)
	7.20%, 01/15/11	Baa1		549,743
460,000	Lear Corp.
	8.11%, 05/15/09	Ba1		541,075
				2,162,733
	Banking - 12.9%
880,000	Bank of America Corp.
	4.88%, 09/15/12	Aa2		884,506
450,000	Bank of New York Co., Inc.
	3.75%, 02/15/08	Aa3		455,267
$1,000,000	Bank of New York Co., Inc.
	6.38%, 04/01/12	A1	$	1,108,522
450,000	BB&T Corp. (b)
	6.38%, 06/30/05	A2		478,897
725,000	Capital One Bank
	4.88%, 05/15/08	Baa2		746,136
470,000	Capital One Bank
	5.75%, 09/15/10	Baa2		497,180
500,000	Citifinancial
	6.75%, 07/01/07	Aa1		559,348
655,000	Fifth Third Bank
	4.50%, 06/01/18	Aa3		608,076
500,000	Firstar Corp.
	7.13%, 12/01/09	Aa3		576,215
350,000	MBNA Corp., MTN
	6.25%, 01/17/07	Baa2		381,042
85,000	MBNA Corp., MTN
	7.50%, 03/15/12	Baa2		98,756
420,000	National City Bank of Indiana
	4.88%, 07/20/07	Aa3		442,136
250,000	Northern Trust Co.
	6.65%, 11/09/04	Aa3		260,522
450,000	Regions Bank
	2.90%, 12/15/06	Aa3		456,717
200,000	Suntrust Banks, Inc.
	6.38%, 04/01/11	Aa3		223,908
125,000	Suntrust Banks, Inc.
	7.75%, 05/01/10	A1		149,705
500,000	U.S. Bancorp, MTN
	5.10%, 07/15/07	Aa3		533,122
455,000	US Bank National Cincinnati
	6.50%, 02/01/08	Aa3		506,428
475,000	Wachovia Bank N.A.
	4.85%, 07/30/07	Aa2		512,123
450,000	Wachovia Corp.
	4.95%, 11/01/06	Aa3		477,774
455,000	Washington Mutual Bank FA
	5.50%, 01/15/13	A3		469,355
450,000	Washington Mutual, Inc.
	4.38%, 01/15/08	A3		462,615
450,000	Wells Fargo & Co.
	5.13%, 02/15/07	Aa1		480,086
450,000	Wells Fargo & Co.
	5.13%, 09/01/12	Aa2		459,795
				11,828,231
	Beverages, Food &
	Tobacco - 4.1%
450,000	Anheuser-Busch Cos., Inc.
	4.63%, 02/01/15	A1		439,133
500,000	Bottling Group LLC
	4.63%, 11/15/12	A3		497,281
460,000	Cadbury Schweppes US Finance LLC (c)
	3.88%, 10/01/08	Baa2		457,911
525,000	Conagra Foods, Inc.
	7.50%, 09/15/05	Baa1		570,389

See Notes to Financial Statements.

F-1

ALLMERICA SECURITIES TRUST

PORTFOLIO OF INVESTMENTS, Continued • December 31, 2003

Par Value		Moody’s Ratings (Unaudited)	Value (Note 2)
	Beverages, Food & Tobacco (continued)
$   450,000	Diageo Capital, Plc
	3.50%, 11/19/07	A2	$	453,879
460,000	General Mills, Inc.
	6.00%, 02/15/12	Baa2		491,909
830,000	Unilever Capital Corp.
	5.90%, 11/15/32	A1		831,991
				3,742,493
	Chemicals - 1.1%
200,000	Du Pont (E.I.) De Nemours and Co.
	8.25%, 09/15/06	Aa3		229,718
500,000	Praxair, Inc.
	6.63%, 10/15/07	A3		556,549
210,000	Sealed Air Corp. (a) (c)
	5.63%, 07/15/13	Baa3		214,891
				1,001,158
	Commercial Services - 2.5%
450,000	Allied Waste North America (c)
	6.50%, 11/15/10	Ba3		461,250
500,000	Allied Waste North America
	8.50%, 12/01/08	Ba3		556,250
750,000	Pitney Bowes, Inc.
	4.75%, 05/15/18	Aa3		715,376
490,000	Waste Management, Inc.
	7.00%, 10/01/04	Baa3		507,089
				2,239,965
	Cosmetics & Personal Care - 1.7%
300,000	Procter & Gamble Co.
	4.75%, 06/15/07	Aa3		317,578
1,000,000	Procter & Gamble Co.
	8.50%, 08/10/09	Aa3		1,234,326
				1,551,904
	Electric Utilities - 7.6%
550,000	AmerenEnergy Generating
	7.75%, 11/01/05	A3		603,087
500,000	Baltimore Gas & Electric Co.
	5.20%, 06/15/33	A2		454,302
505,000	CenterPoint Energy, Inc. (a) (c)
	5.88%, 06/01/08	Ba1		526,085
600,000	Dayton Power & Light Co. (c)
	5.13%, 10/01/13	Baa1		598,812
425,000	Detroit Edison Co.
	6.13%, 10/01/10	A3		466,253
580,000	Dominion Resources, Inc.
	5.25%, 08/01/33	Baa1		574,380
500,000	Duke Energy Corp.
	7.50%, 08/16/05	Baa2		537,231
563,466	East Coast Power LLC
	7.07%, 03/31/12	Baa3		569,101
250,000	Entergy Gulf States, Inc. (c)
	3.60%, 06/01/08	Baa3		240,979
$   450,000	FirstEnergy Corp.
	6.45%, 11/15/11	Baa2	$	466,402
225,000	Florida Power & Light
	6.88%, 12/01/05	Aa3		244,781
600,000	Gulf States Utilities (d)
	8.25%, 04/01/04	BBB-		609,422
500,000	Pinnacle Partners (c)
	8.83%, 08/15/04	Ba2		518,125
450,000	TXU Energy Co.
	7.00%, 03/15/13	Baa2		497,698
				6,906,658
	Entertainment & Leisure - 1.9%
450,000	AOL Time Warner, Inc.
	6.15%, 05/01/07	Baa1		489,616
500,000	Harrah’s Operating Co., Inc.
	7.13%, 06/01/07	Baa3		556,795
350,000	Park Place Entertainment Corp. (a)
	8.13%, 05/15/11	Ba2		392,437
300,000	Time Warner Cos., Inc.
	7.57%, 02/01/24	Baa1		339,259
				1,778,107
	Financial Services - 8.3%
500,000	American Express Co.
	3.75%, 11/20/07	A1		509,322
525,000	American Express Credit Corp.
	3.00%, 05/16/08	Aa3		513,803
460,000	Ford Motor Credit Co. (a)
	6.50%, 01/25/07	A3		490,003
400,000	Ford Motor Credit Co.
	6.88%, 02/01/06	A3		426,923
825,000	Ford Motor Credit Co.
	7.25%, 10/25/11	A3		894,765
500,000	General Electric Capital Corp.
	8.75%, 05/21/07	Aaa		592,711
500,000	General Electric Capital Corp., MTN
	4.25%, 01/15/08	Aaa		517,091
380,000	General Motors
	Acceptance Corp., MTN (b)
	2.41%, 10/20/05	A3		382,853
500,000	Household Finance Corp.
	8.00%, 07/15/10	A1		598,791
450,000	International Lease Finance Corp.
	4.35%, 09/15/08	A1		459,236
425,000	J. Paul Getty Trust
	5.88%, 10/01/33	Aaa		420,681
100,000	KFW International Finance, Inc.
	4.25%, 04/18/05	Aaa		103,435
500,000	Mellon Funding Corp.
	5.00%, 12/01/14	A2		501,261
550,000	Pitney Bowes Credit Corp.
	8.55%, 09/15/09	Aa3		670,916
500,000	Toyota Motor Credit Corp.
	5.50%, 12/15/08	Aaa		547,175
				7,628,966

See Notes to Financial Statements.

F-2

ALLMERICA SECURITIES TRUST

PORTFOLIO OF INVESTMENTS, Continued • December 31, 2003

Par Value		Moody’s Ratings (Unaudited)	Value (Note 2)
	Food Retailers - 2.5%
$   675,000	Delhaize America, Inc.
	8.13%, 04/15/11	Ba1	$	776,250
470,000	Kroger Co.
	5.50%, 02/01/13	Baa3		478,034
450,000	Safeway, Inc.
	6.50%, 03/01/11	Baa2		491,231
500,000	Safeway, Inc.
	9.65%, 01/15/04	Baa3		500,793
				2,246,308
	Forest Products & Paper - 3.5%
500,000	International Paper Co.
	5.30%, 04/01/15	Baa2		488,791
350,000	International Paper Co.
	7.50%, 05/15/04	Baa2		356,990
500,000	Kimberly-Clark Corp.
	7.10%, 08/01/07	Aa2		570,635
750,000	Rock-Tenn Co.
	5.63%, 03/15/13	Baa3		754,475
450,000	Weyerhaeuser Co.
	5.25%, 12/15/09	Baa2		467,326
500,000	Weyerhaeuser Co.
	6.75%, 03/15/12	Baa2		545,470
				3,183,687
	Health Care Providers - 0.6%
550,000	HCA, Inc.
	6.75%, 07/15/13	Ba1		583,274
	Home Construction,
	Furnishings & Appliances - 0.6%
500,000	Pulte Corp.
	8.13%, 03/01/11	Baa3		593,698
	Industrial - Diversified - 0.9%
750,000	Illinois Tool Works, Inc.
	6.88%, 11/15/08	Aa3		859,621
	Insurance - 1.9%
450,000	Marsh & McLennan Cos., Inc.
	4.85%, 02/15/13	A2		443,065
710,000	Medco Health Solutions, Inc.
	7.25%, 08/15/13	Ba1		774,575
450,000	UnitedHealth Group, Inc.
	7.50%, 11/15/05	A3		494,019
				1,711,659
	Media - Broadcasting &
	Publishing - 4.0%
270,000	Belo Corp.
	8.00%, 11/01/08	Baa3		315,089
450,000	Continental Cablevision, Inc., Senior Notes
	8.30%, 05/15/06	Baa3		504,531
505,000	Cox Communications, Inc.
	7.13%, 10/01/12	Baa2		582,474
$   225,000	Cox Enterprises, Inc. (c)
	4.38%, 05/01/08	Baa1	$	228,573
700,000	Echostar DBS Corp. (c)
	5.75%, 10/01/08	Ba3		707,875
500,000	News America Holdings, Inc.
	7.38%, 10/17/08	Baa3		570,462
180,000	Viacom, Inc.
	5.50%, 05/15/33	A3		167,630
450,000	Viacom, Inc.
	7.88%, 07/30/30	A3		559,769
				3,636,403
	Oil & Gas - 7.6%
500,000	ANR Pipeline Co., Debenture
	9.63%, 11/01/21	B1		594,375
375,000	Burlington Resources, Inc.
	7.40%, 12/01/31	Baa1		443,930
580,000	Conoco Funding Co.
	5.45%, 10/15/06	A3		622,280
500,000	Conoco Funding Co.
	7.25%, 10/15/31	A3		590,045
230,000	Enterprise Products
	7.50%, 02/01/11	Baa2		257,028
350,000	Enterprise Products
	8.25%, 03/15/05	Baa2		373,937
300,000	Marathon Oil Corp.
	6.13%, 03/15/12	Baa1		324,434
110,000	Occidental Petroleum Corp.
	5.88%, 01/15/07	Baa1		119,336
500,000	Occidental Petroleum Corp.
	6.50%, 04/01/05	Baa1		528,482
625,000	Phillips Petroleum
	8.50%, 05/25/05	A3		681,326
690,000	Pioneer Natural Resource Co.
	7.50%, 04/15/12	Ba1		793,042
600,000	Texaco Capital, Inc.
	8.25%, 10/01/06	Aa3		695,657
435,000	Valero Energy Corp.
	6.13%, 04/15/07	Baa3		472,259
400,000	XTO Energy, Inc.
	7.50%, 04/15/12	Ba2		452,000
				6,948,131
	Pharmaceuticals - 2.3%
700,000	Bergen Brunswig Corp. (d)
	7.25%, 06/01/05	BB		731,500
120,000	Johnson & Johnson
	6.73%, 11/15/23	Aaa		136,743
750,000	Lilly (Eli) & Co.
	7.13%, 06/01/25	Aa3		886,586
330,000	Zeneca Wilmington
	7.00%, 11/15/23	Aa2		382,305
				2,137,134

See Notes to Financial Statements.

F-3

ALLMERICA SECURITIES TRUST

PORTFOLIO OF INVESTMENTS, Continued • December 31, 2003

Par Value		Moody’s Ratings (Unaudited)	Value (Note 2)
	Retailers - 2.8%
$   500,000	J.C. Penney Co., Inc.
	7.38%, 08/15/08	Ba3	$	555,625
500,000	Kohls Corp.
	6.00%, 01/15/33	A3		501,360
890,000	Target Corp.
	6.35%, 11/01/32	A2		934,892
450,000	Wal-Mart Stores, Inc.
	7.55%, 02/15/30	Aa2		553,809
				2,545,686
	Securities Broker - 2.7%
580,000	Bear Stearns Cos., Inc.
	4.00%, 01/31/08	A1		590,749
450,000	Goldman Sachs Group, Inc.
	5.70%, 09/01/12	Aa3		472,928
333,153	Jones (Edward D.) & Co., LP (e) (f)
	7.95%, 04/15/06	NR		355,683
500,000	Lehman Brothers Holdings, Inc.
	4.00%, 01/22/08	A1		509,972
495,000	Morgan Stanley Dean Witter & Co.
	6.60%, 04/01/12	Aa3		552,835
				2,482,167
	Telephone Systems - 2.1%
500,000	BellSouth Corp.
	6.88%, 10/15/31	A1		547,069
680,000	Sprint Capital Corp.
	6.13%, 11/15/08	Baa3		724,796
120,000	Sprint Capital Corp.
	7.90%, 03/15/05	Baa3		127,832
450,000	Verizon Florida, Inc.
	6.13%, 01/15/13	A1		481,580
				1,881,277
	Transportation - 1.2%
450,000	Consolidated Rail Corp.
	9.75%, 06/15/20	Baa2		620,017
255,000	Union Pacific Corp.
	5.38%, 06/01/33	Baa2		232,439
250,000	Union Pacific Corp.
	6.63%, 02/01/08	Baa2		277,509
				1,129,965
	Total Corporate Notes and Bonds			69,750,461
	(Cost $67,312,087)
ASSET-BACKED AND MORTGAGE-BACKED SECURITIES (h) - 6.3%
1,000,000	American Airlines, Inc.,
	Pass-Through Trust,
	Series 1991 - C2
	9.73%, 09/29/14	Caa2		725,450
570,000	Bear Stearns Commercial Mortgage
	Securities, Inc., Series 2002-PBW1,
	Class A2
	4.72%, 11/11/35	Aaa		573,475
$   250,000	Bear Stearns Mortgage
	Securities, Inc., Series 1999-WF2,
	Class A2, CMO
	7.08%, 06/15/09	Aaa	$	284,324
300,000	Citibank Credit Card Issuance
	Trust, Series 2000-Cl, CMO
	6.88%, 11/16/09	Aaa		341,611
500,000	General Electric Capital
	Commercial Mortgage Corp.,
	Series 2002-1A, Class A3
	6.27%, 12/10/35	Aaa		553,198
70,246	Green Tree Recreation
	Equipment & Consumer Trust,
	Series 1997-B, Class A1, CMO (d)
	6.55%, 07/15/28	AAA		70,347
500,000	GS Mortgage Securities Corp II,
	Series 1997-GL, Class A2D
	6.94%, 07/13/30	Aaa		558,178
250,000	MBNA Master Credit Card Trust,
	Series 1995-C, Class A
	6.45%, 02/15/08	Aaa		266,531
250,000	Morgan Stanley Dean Witter Capital I,
	Series 2002-TOP7, Class B, CMO
	6.08%, 01/15/39	Aa2		272,741
750,000	Morgan Stanley Dean Witter Capital I,
	Series 2003-T0P9, Class A2, CMO (d)
	4.74%, 11/13/36	AAA		751,353
184,769	Toyota Auto Receivables Owner Trust,
	Series 2002-B, Class A3
	3.76%, 06/15/06	Aaa		187,126
1,000,000	Union Acceptance Corp.,
	Series 2000-B, Class B
	7.73%, 01/08/08	Aaa		1,043,977
189,892	USAA Auto Owner Trust,
	Series 2000-1, Class A4
	6.98%, 06/15/05	Aaa		191,800
	Total Asset-Backed and
	Mortgage-Backed Securities			5,820,111
	(Cost $6,065,722)
FOREIGN GOVERNMENT OBLIGATIONS (i) - 2.9%
450,000	Province of British Columbia
	5.38%, 10/29/08	Aa2		486,540
550,000	Province of Manitoba
	4.25%, 11/20/06	Aa2		572,542
500,000	Province of Ontario
	2.63%, 12/15/05	Aa2		503,435
500,000	Province of Quebec
	6.13%, 01/22/11	A1		557,351
450,000	Province of Quebec
	7.00%, 01/30/07	A1		505,089
	Total Foreign Government Obligations			2,624,957
	(Cost $2,472,866)

See Notes to Financial Statements.

F-4

ALLMERICA SECURITIES TRUST

PORTFOLIO OF INVESTMENTS, Continued • December 31, 2003

Par Value		Moody’s Ratings (Unaudited)	Value (Note 2)
FOREIGN BONDS (i) - 8.8%
$   500,000	Alberta Energy Co., Ltd.
	7.38%, 11/01/31	Baa1	$	593,779
700,000	British Sky Broadcasting Group, Plc
	7.30%, 10/15/06	Baa3		779,428
450,000	British Telecom, Plc (g)
	8.13%, 12/15/10	Baa1		547,594
500,000	Calpine Canada Energy Finance
	8.50%, 05/01/08	Caa1		398,750
355,000	Canadian Pacific, Ltd.
	9.45%, 08/01/21	Baa2		483,893
450,000	Canadian Pacific Railroad
	5.75%, 03/15/33	Baa2		435,626
790,000	Royal Bank of Scotland Group, Plc
	4.70%, 07/03/18	Aa3		728,888
450,000	Sappi Papier Holding AG (c)
	6.75%, 06/15/12	Baa2		491,912
1,000,000	St. George Bank, Ltd., Yankee Debenture (c)
	7.15%, 10/15/05	A3		1,084,355
435,000	Stora Enso Oyj
	7.38%, 05/15/11	Baa1		503,336
500,000	Telus Corp.
	7.50%, 06/01/07	Ba1		559,572
490,000	Tyco International Group S.A.
	6.38%, 10/15/11	Ba2		523,688
450,000	Vodafone Group, Plc
	5.38%, 01/30/15	A2		454,169
500,000	Vodafone Group, Plc
	6.25%, 11/30/32	A2		509,955
	Total Foreign Bonds			8,094,945
	(Cost $7,829,340)
MUNICIPAL OBLIGATIONS - 0.8%
750,000	Illinois State General Obligation
	3.85%, 06/01/13	Aa3		700,342
	Total Municipal Obligations			700,342
	(Cost $748,583)
Shares
INVESTMENT COMPANY - 1.0%
929,365	Marshall Money Market Fund	NR		929,365
	Total Investment Company			929,365
	(Cost $929,365)
Total Investments - 99.3%				90,825,286
(Cost $88,306,255)
Net Other Assets and Liabilities - 0.7%				632,939
Total Net Assets - 100.0%			$	91,458,225

(a) All or a portion of this security is out on loan at December 31, 2003; the value of the securities loaned amounted to $1,891,692 The value of collateral amounted to $1,939,350 which consisted of cash equivalents.

(b) Variable rate security. The rate shown reflects rate in effect at period end.

(c) Security exempt from registration under Rule 144A of the Securities Act of 1933. This security may be resold in transactions exempt from registration, to qualified institutional buyers. At December 31, 2003 these securities amounted to $5,530,768 or 6.0% of net assets.

(d) Standard & Poor’s (S&P) credit ratings are used in the absence of a rating by Moody’s Investors, Inc.

(e) Security is valued by management (Note 2).

(f) Restricted Security - Represents ownership in a private placement investment which has not been registered with the Securities and Exchange Commission under the Securities Act of 1933. At December 31, 2003, these securities amounted to $355,683 or 0.4% of net assets.

(g) Debt obligation initially issued in coupon form which converts to a higher coupon form at a specified date and rate. The rate shown is the rate at period end. The maturity date shown is the ultimate maturity.

(h) Pass Through Certificates.

(i) U.S. currency denominated.

CMO Collateralized Mortgage Obligation.

MTN Medium Term Note.

NR Not Rated.

FEDERAL INCOME TAX INFORMATION (SEE NOTE 2)

At December 31, 2003, the aggregate cost of investment securities for tax purposes was $88,935,555. Net unrealized appreciation (depreciation) aggregated $1,889,731, of which $3,069,973 related to appreciated investment securities and $(1,180,242) related to depreciated investment securities.

As of December 31, 2003, the components of distributable earnings (excluding unrealized appreciation disclosed above) on a tax basis consisted of $6,241,075 of capital loss carryforwards.

For the year ended December 31, 2003, the Portfolio has elected to defer $872,122 of capital losses attributable to Post-October losses.

During the year ended December 31, 2003, the tax character of distributions paid for ordinary income was $4,854,653.

At December 31, 2003, the Portfolio had capital loss carryforwards which expire as follows: $1,365,128 in 2008; $2,362,884 in 2009; $2,513,063 in 2010.

See Notes to Financial Statements.

F-5

ALLMERICA SECURITIES TRUST

PORTFOLIO OF INVESTMENTS, Continued • December 31, 2003

OTHER INFORMATION

For the year ended December 31, 2003, the aggregate cost of purchases and the proceeds of sales, other than from short-term investments, included $50,749,143 and $30,059,726 of non-governmental issuers, respectively, and $39,431,542 and $57,748,767 of U.S Government and Agency issuers, respectively.

The composition of ratings of both long-term and short-term debt holdings as a percentage of total value of investments in securities is as follows:

Moody’s Rating

(Unaudited)

Aaa	7.9	%
Aa	22.5	%
A	24.8	%
Baa	28.1	%
Ba	9.6	%
B	0.7	%
Caa	1.2	%
NR (Not Rated)	2.8	%
	97.6	%

S&P Ratings

(Unaudited)

AAA	0.9	%
BBB	0.7	%
BB	0.8	%
	2.4	%

See Notes to Financial Statements.

F-6

ALLMERICA SECURITIES TRUST

STATEMENT OF ASSETS AND LIABILITIES • December 31, 2003

ASSETS:
Investments:
Investments at cost	$	88,306,255
Net unrealized appreciation		2,519,031
Total investments at value†		90,825,286
Cash		12,094
Short-term investments held as collateral for securities loaned		1,939,350
Interest receivable		1,278,150
Total Assets		94,054,880
LIABILITIES:
Payable for investments purchased		523,002
Collateral for securities loaned		1,939,350
Management fee payable		36,691
Trustees’ fees and expenses payable		5,177
Accrued expenses and other payables		92,435
Total Liabilities		2,596,655
NET ASSETS	$	91,458,225
NET ASSETS consist of:
Par Value	$	8,592,306
Paid-in capital		88,089,385
Distribution in excess of net investment income		(629,300	)
Accumulated net realized loss		(7,113,197	)
Net unrealized appreciation		2,519,031
TOTAL NET ASSETS	$	91,458,225
Shares of beneficial interest outstanding (10,000,000 authorized shares with par value of $1.00)		8,592,306
NET ASSET VALUE
Per share	$	10.644
MARKET VALUE (closing price on New York Stock Exchange)
Per share	$	9.75
†Total value of securities on loan	$	1,891,692

See Notes to Financial Statements.

F-7

ALLMERICA SECURITIES TRUST

STATEMENT OF OPERATIONS • For the Year Ended December 31, 2003

INVESTMENT INCOME
Interest	$	4,795,582
Securities lending income		6,248
Total investment income		4,801,830
EXPENSES
Management fees		407,059
Custodian and Fund accounting fees		64,348
Transfer agent fees		63,191
Legal fees		2,726
Audit fees		21,887
Trustees’ fees and expenses		14,772
Reports to shareholders		16,868
New York Stock Exchange fees		22,874
Miscellaneous		8,730
Total expenses		622,455
NET INVESTMENT INCOME		4,179,375
NET REALIZED AND UNREALIZED GAIN (LOSS) ON INVESTMENTS:
Net realized gain on investments sold		863,113
Net change in unrealized appreciation (depreciation) of investments		436,219
NET GAIN ON INVESTMENTS		1,299,332
NET INCREASE IN NET ASSETS RESULTING FROM OPERATIONS	$	5,478,707

STATEMENTS OF CHANGES IN NET ASSETS

	Years Ended December 31,
	2003			2002
NET ASSETS at beginning of year	$	90,834,171		$	90,773,702
INCREASE (DECREASE) IN NET ASSETS RESULTING FROM OPERATIONS:
Net investment income		4,179,375			4,857,694
Net realized gain (loss) on investments sold		863,113			(2,344,097	)
Net change in unrealized appreciation (depreciation) of investments		436,219			2,573,374
Net increase in net assets resulting from operations		5,478,707			5,086,971
Distributions To Shareholders From Net Investment Income		(4,854,653	)		(5,026,502	)
Total increase in net assets		624,054			60,469
NET ASSETS at end of year	$	91,458,225		$	90,834,171
Distribution in excess of net investment income	$	(629,300	)	$	(376,040	)

See Notes to Financial Statements.

F-8

ALLMERICA SECURITIES TRUST

FINANCIAL HIGHLIGHTS - For a Share Outstanding Throughout Each Year

	Year ended December 31,
	2003			2002			2001(1)			2000			1999
Net Asset Value, beginning of year	$	10.572		$	10.565		$	10.866		$	10.958		$	11.961
Income from Investment Operations:
Net investment income		0.486			0.565			0.673	(2)		0.802			0.802
Net realized and unrealized gain (loss) on investments		0.151			0.027			(0.209	)		(0.084	)		(0.965	)
Total from investment operations		0.637			0.592			0.464			0.718			(0.163	)
Less Distributions:
Dividends from net investment income		(0.565	)		(0.585	)		(0.729	)		(0.800	)		(0.800	)
Distributions from net realized capital gains		—			—			—			(0.010	)		(0.040	)
Return of capital		—			—			(0.036	)		—			—
Total distributions		(0.565	)		(0.585	)		(0.765	)		(0.810	)		(10.840	)
Net increase (decrease) in net asset value		0.072			0.007			(0.301	)		(0.092	)		(1.003	)
Net Asset Value, end of year	$	10.644		$	10.572		$	10.565		$	10.866		$	10.958
Market Value, end of year	$	9.75		$	9.45		$	9.83		$	10.00		$	8.81
Total Return on Market Value, end of year		9.38	%		2.11	%		6.00	%		23.76	%		(13.75	)%
Ratios/Supplemental Data
Net assets, end of year (000’s)	$	91,458		$	90,834		$	90,774		$	93,362		$	94,157
Ratios to average net assets:
Net investment income		4.56	%		5.38	%		6.23	%		7.38	%		7.00	%
Operating expenses		0.68	%		0.86	%		0.79	%		0.74	%		0.77	%
Management fee		0.44	%		0.45	%		0.50	%		0.50	%		0.49	%
Portfolio turnover rate		98	%		79	%		128	%		58	%		24	%

(1) Effective January 1, 2001, the Trust adopted the provisions of the AICPA Audit and Accounting Guide for Investment Companies and is amortizing premium and market discount on debt securities using the daily effective yield method. The effect of this change for the year ended December 31, 2001 was a decrease in net investment income per share of $0.022, an increase in net realized and unrealized gains and losses per share of $0.022 and a decrease in the ratio of net investment income to average net assets from 6.36% to 6.23%. Per share data and ratio/supplemental data for periods prior to January 1, 2001 have not been restated to reflect this change in presentation.

(2) Computed using average shares throughout the period.

See Notes to Financial Statements.

F-9

ALLMERICA SECURITIES TRUST

NOTES TO FINANCIAL STATEMENTS

1. ORGANIZATION

Allmerica Securities Trust (the “Trust”) was organized as a Massachusetts business trust on June 30, 1986, and is registered under the Investment Company Act of 1940, as amended, as a diversified, closed-end management investment company.

2. SIGNIFICANT ACCOUNTING POLICIES

The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions at the date of the financial statements. Actual results could differ from those estimates.

The following is a summary of significant accounting policies followed by the Trust in the preparation of its financial statements:

Security Valuation: Corporate debt securities and debt securities of the U.S. Government and its agencies (other than short-term investments) are valued using an independent pricing service approved by the Board of Trustees which utilizes market quotations and transactions, quotations from dealers and various relationships among securities in determining value. If not valued by a pricing service, such securities are valued at prices obtained from independent brokers. Investments with prices that cannot be readily obtained are carried at fair value as determined in good faith under consistently applied procedures established by and under the supervision of the Board of Trustees. Short-term investments that mature in 60 days or less are valued at amortized cost. This method involves valuing a portfolio security initially at its cost and thereafter assumes a constant amortization to maturity of any discount or premium.

At December 31, 2003, one security with a value of $355,683 or 0.4% of net assets was valued by management under the direction of the Board of Trustees.

Security Transactions and Investment Income: Security transactions are recorded as of the trade date. Realized gains and losses from security transactions are determined on the basis of identified cost. Interest income, including amortization of premium and accretion of discount on securities, is accrued daily. Income distributions earned by the Trust from investments in certain investment companies are recorded as interest income in the accompanying financial statements.

Federal Taxes: The Trust intends to continue to qualify as a “regulated investment company” under Subchapter M of the Internal Revenue Code of 1986, as amended. By so qualifying, the Trust will not be subject to Federal income taxes to the extent it distributes all of its taxable income and net realized gains, if any, for its fiscal year. In addition, by distributing during each calendar year substantially all of its net investment income, capital gains and certain other amounts, if any, the Trust will not be subject to Federal excise tax. Therefore, no Federal income tax provision is required.

Distributions to Shareholders: Dividends to shareholders resulting from net investment income are recorded on the ex-dividend date and paid quarterly Net realized capital gains, if any, are distributed at least annually. Income and capital gains distributions are determined in accordance with income tax regulations. Differences between book basis and tax basis amounts are primarily due to differing book and tax treatments in both the timing of the recognition of losses deferred due to wash sales and differing treatments for the amortization of premium and market discount. Permanent book and tax basis differences relating to shareholder distributions will result in reclassifications to paid in capital. Permanent book-tax differences, if any, are not included in ending undistributed net investment income for the purpose of calculating net investment income per share in the Financial Highlights.

Securities Lending: The Trust, using Investors Bank & Trust Company (“IBT”) as its lending agent, may loan securities to brokers and dealers in exchange for negotiated lenders’ fees. These fees are disclosed as “Securities lending income” in the Statement of Operations. The Trust receives collateral against the loaned securities, which must be maintained at not less than 102% of the market value of the loaned securities during the period of the loan. Collateral received is generally

F-10

ALLMERICA SECURITIES TRUST

NOTES TO FINANCIAL STATEMENTS (Continued)

cash, and is invested in short term investments. Lending portfolio securities involves possible delays in receiving additional collateral or in the recovery of the securities or possible loss of rights in the collateral. Information regarding the value of the securities loaned and the value of the collateral at period end is included in a footnote at the end of the Trust’s Portfolio of Investments.

Expenses: Most expenses of the Trust can be directly attributable to the Trust. Expenses which cannot be directly attributable to the Trust are allocated based upon relative net assets among the Trust and one other affiliated registered investment company, Allmerica Investment Trust (comprised of nine separate portfolios).

3. INVESTMENT MANAGEMENT AND OTHER RELATED PARTY TRANSACTIONS

Opus Investment Management, Inc., a direct, wholly-owned subsidiary of Allmerica Financial Corporation (“Allmerica Financial”) serves as Investment Manager to the Trust. For these services, the Trust pays Opus an aggregate monthly compensation at the annual rate of (a) 3/10 of 1% of average net assets plus (b) 2-1/2% of the amount of interest income.

To the extent that normal operating expenses of the Trust, excluding taxes, interest, brokerage commissions and extraordinary expenses, but including the investment management fee, exceed 1.50% of the first $30,000,000 of the Trust’s average weekly net assets, and 1.00% of any excess of such value over $30,000,000, Opus will bear such excess expenses.

IBT performs fund administration, custodian and fund accounting services for the Trust. IBT is entitled to receive a fee for these services, in addition to certain out-of-pocket expenses. Opus is solely responsible for the payment of the administration fee and the Trust pays the fees for the fund accounting and custodian services to IBT.

The Trust pays no salaries or compensation to any of its officers. Trustees who are not directors, officers or employees of the Trust or the Investment Manager are reimbursed for their travel expenses in attending meetings of the Trustees and receive fees for their services. Such amounts are paid by the Trust.

4. SHARES OF BENEFICIAL INTEREST

There are 10,000,000 shares of $1.00 par value common stock authorized. At December 31, 2003, First Allmerica Financial Life Insurance Company, an indirect, wholly-owned subsidiary of Allmerica Financial, the Trustees and the officers of the Trust owned in the aggregate 121,553 shares of beneficial interest.

5. RESTRICTED SECURITIES

At December 31, 2003, the Trust owned the following restricted security constituting 0.4% of net assets, which may not be publicly sold without registration under the Securities Act of 1933. The Trust would bear the registration costs in connection with the disposition of restricted securities held in the portfolio. The Trust does not have the right to demand that such securities be registered. The value of restricted securities is determined by valuations supplied by a pricing service or brokers or, if not available, in good faith by or at the direction of the Board of Trustees. Additional information on the restricted security is as follows:

Issuer	Date of Acquisition	Par Amount		Cost at Acquisition		Value
Jones (Edward D.) & Co., LP	05/06/94	$	333,153	$	333,153	$	355,683

F-11

ALLMERICA SECURITIES TRUST

REPORT OF INDEPENDENT AUDITORS

To the Board of Trustees and Shareholders of Allmerica Securities Trust

In our opinion, the accompanying statement of assets and liabilities, including the portfolio of investments (except for Moody’s and S&P Ratings), and the related statements of operations and of changes in net assets and the financial highlights present fairly, in all material respects, the financial position of the Allmerica Securities Trust (hereafter referred to as the “Trust”) at December 31, 2003, the results of its operations, the changes in its net assets, and the financial highlights for the periods indicated, in conformity with accounting principles generally accepted in the United States of America .These financial statements and financial highlights (hereafter referred to as “financial statements”) are the responsibility of the Trust’s management; our responsibility is to express an opinion on these financial statements based on our audits. We conducted our audits of these financial statements in accordance with auditing standards generally accepted in the United States of America, which require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement. An audit includes examining, on a test basis, evidence supporting the amounts and disclosures in the financial statements, assessing the accounting principles used and significant estimates made by management, and evaluating the overall financial statement presentation. We believe that our audits, which included confirmation of securities at December 31, 2003 by correspondence with the custodian and brokers, provide a reasonable basis for our opinion.

PricewaterhouseCoopers LLP

Boston, Massachusetts

February 2, 2004

F-12

ALLMERICA SECURITIES TRUST

BOARD OF TRUSTEES (Unaudited)

Name, Address and Age(1)	Position(s) Held with Trust	Term of Office and Length of Time Served	Principal Occupation(s) During Past 5 Years(2)	Number of Portfolios in Fund Complex Overseen by Trustee	Other Directorships Held by Trustee
P. Kevin Condron (58)	Trustee, Member of the Audit Committee and Fund Operations Committee	1 Year Term Served Since 1998	President and Chief Executive Officer, The Granite Group (wholesale plumbing and heating), 1997-present.	10	Director, Banknorth Group.
Jocelyn S. Davis (50)	Trustee, Member of the Audit Committee and Fund Operations Committee	1 Year Term Served Since 2001	President, Nelson Hart, LLC (consulting), 2002-present; Beers & Cutler (professional services), 2001-2002; Chief Financial Officer, AARP (non-profit), 1996-2001.	10	None
Cynthia A. Hargadon (49)	Trustee, Member of the Fund Operations Committee, Investment Operations Committee and Governance Committee	1 Year Term Served Since 1997	President and Chief Investment Officer, PlanTools, LLC (consulting), 2003-present; Managing Director, McHenry Group, 2003-present; President, Hargadon Associates (asset management consulting), 2002-2003; President, Potomac Asset Management, Inc., 2000-2002; Director of Investments, National Automobile Dealers Association, 1999-2000; President, Stable Value Investment Association (investment trade group), 1996-1999.	10	Director, Wilshire Target Funds, 2001-present.
T. Britton Harris, IV (45)	Trustee, Member of the Investment Operations Committee, Governance Committee and Fund Operations Committee	1 Year Term Served Since 2001	President, Verizon Investment Management Corporation, 1990-present.	10	None
Gordon Holmes (65)	Trustee, Chairman of the Audit Committee and Member of the Fund Operations Committee	1 Year Term Served Since 1991	Instructor at Bentley College, 1998-present; Certified Public Accountant; Retired Partner, Tofias, Fleishman, Shapiro & Co., P.C. (Accountants).	10	None
Attiat F. Ott (68)	Trustee, Chairman of the Fund Operations Committee and Member of the Audit Committee	1 Year Term Served Since 1982	Professor of Economics and Director of the Institute for Economic Studies, Clark University, 940 Main Street, Worcester, MA.	10	None
Ranne P. Warner (59)	Trustee, Chairman of the Governance Committee, Member of the Fund Operations Committee and Investment Operations Committee	1 Year Term Served Since 1991	President, Centros Properties, USA; Owner, Ranne P. Warner and Company; Blackstone Exchange LLC (real estate) 2001-present.	10	Director, Wainwright Bank & Trust Co. (commercial bank).
*Mark A. Hug (46)	Trustee, Member of the Investment Operations Committee	1 Year Term Served Since 2003	President and CEO, First Allmerica Financial Life Insurance Company (“First Allmerica”) and Allmerica Financial Life Insurance and Annuity Company (“Allmerica Financial Life”), 2000-present; Senior Vice President, Equitable Life (product and marketing) prior to 1999.	10	None

F-13

ALLMERICA SECURITIES TRUST

BOARD OF TRUSTEES (Unaudited) (Continued)

Name, Address and Age(1)	Position(s) Held with Trust	Term of Office and Length of Time Served	Principal Occupation(s) During Past 5 Years(2)	Number of Portfolios in Fund Complex Overseen by Trustee	Other Directorships Held by Trustee
*John P. Kavanaugh (49)	Chairman, Trustee and President, Chairman of the Investment Operations Committee	1 Year Term Served Since 1995	President, Opus Investment Management, Inc.; Vice President, Director, Chief Investment Officer, First Allmerica and Allmerica Financial Life.	10	None

* Messrs. Hug and Kavanaugh are “interested persons”, as defined in the Investment Company Act of 1940 as amended, of the Trust and of Allmerica Financial Corporation (“AFC”) because of their affiliations with AFC.

(1) The business address of each person is 440 Lincoln Street, Worcester, Massachusetts 01653.

(2) Except as otherwise noted, each individual has held the office indicated or other offices in the same organization for the last five years.

F-14

ALLMERICA SECURITIES TRUST

REGULATORY DISCLOSURES (Unaudited)

The performance data quoted represents past performance and the investment return and principal value of an investment will fluctuate so that an investor’s shares, when redeemed, may be worth more or less than their original cost.

This report is authorized for distribution to existing shareholders of Allmerica Securities Trust.

SHAREHOLDER TAX INFORMATION (Unaudited)

The portion of the Trust dividends that was derived from U.S. Government obligations in 2003 and may be exempt from state income taxation is 10.65%. The states of California, Connecticut, New York, and New Jersey have exclusionary provisions; however, each of these states has a threshold requirement that must be met before the exclusion applies. During 2003, the level of exempt income did not meet these thresholds and the exclusions did not apply. All other states and the District of Columbia do not tax dividends attributable to U.S. Government obligations within the Trust.

Certain states also require, for intangible tax reporting purposes, the reporting of the percentage of assets invested in either state specific or state specific and federal obligations. The percentage applicable to the states of Florida and Kansas is 3.09%. The percentage applicable to the state of West Virginia, which is only for amounts invested in West Virginia obligations, is 0%.

SHAREHOLDER INFORMATION (Unaudited)

Automatic Dividend Investment Plan: As a shareholder, you may participate in the Trust’s Automatic Dividend Investment Plan. Under the plan, dividends and other distributions are automatically invested in additional full and fractional shares of the Trust to be held on deposit in your account. Such dividends and other distributions are invested at the net asset value if lower than market price plus brokerage commission or, if higher, at the market price plus brokerage commission. You will receive a statement after each payment date for a dividend or other distribution that will show the details of the transaction and the status of your account. You may terminate or rejoin at any time.

Cash Investment Plan: The cash investment plan provides a systematic, convenient and inexpensive means to increase your investment in the Trust by putting your cash to work .The plan permits you to invest amounts ranging from $25 to $1,000 in any one month to purchase additional shares of the Trust. Regular monthly investment is not required.

Your funds are consolidated with funds of other participants to purchase shares. Shares are purchased in bulk and you realize the commission savings. You pay only a service charge of $1.00 per transaction and your proportionate share of the brokerage commission.

Your account will be credited with full and fractional shares purchased. Following each investment, you will receive a statement showing the details of the transaction and the current status of the account. The plan is voluntary and you may terminate at any time.

Investment Manager: Opus Investment Management, Inc.

Portfolio Management: All investment decisions for the Trust will be made by an investment management team.

Investment Objectives: The Trust’s primary investment objective is to provide a high rate of current income, with capital appreciation as a secondary objective.

(There is no guarantee that the Trust will achieve its investment objectives and an investor in the Trust could lose money.)

F-15

ALLMERICA SECURITIES TRUST

SHAREHOLDER INFORMATION (Unaudited) (Continued)

Principal Investment Policies: The Trust seeks to achieve its objectives by investing in various types of fixed income securities with an emphasis on corporate debt obligations. Examples of the types of securities in which the Trust invests are corporate bonds, notes and debentures; mortgage-backed and asset-backed securities; obligations issued or guaranteed by the U.S. Government, its agencies and instrumentalities; and money market instruments. The Trust may invest up to 30% of its assets in high yield securities or “junk bonds” rated below investment grade but at least B- or higher by Moody’s Investors Services or Standard & Poor’s Rating Services or similar rating organizations, and in unrated securities determined by the Investment Manager to be of comparable quality. The Trust may invest up to 25% of its assets in U.S. dollar denominated foreign debt securities. The Trust may invest in securities with relatively long maturities as well as securities with shorter maturities.

Securities issued by some U.S. Government-sponsored entities, such as the Federal Home Loan Mortgage Corporation (Freddie Mac) and the Federal National Mortgage Association (Fannie Mae), are not backed by the full faith and credit of the U.S. Government. No assurances can be given that the U.S. Government would provide financial support to a U.S. Government-sponsored instrumentality if not obligated to do so.

Principal Risks of investing in the Trust:

• Company Risk means that investments in a company often fluctuate based on factors such as earnings, changes in management or products or potential for takeovers or acquisition.

• Credit Risk is the risk that a fixed income security will not be able to pay interest and principal. “Junk bonds,” for example, have a high level of credit risk.

• Foreign Investment Risk involves risks relating to political, social and economic developments abroad.

• Interest Rate Risk means that, when interest rates rise, the prices of fixed income securities will generally fall and, when interest rates fall, the prices of fixed income securities will generally rise.

• Investment Management Risk is the risk that a fund does not achieve its investment objective despite the investment strategies used by the investment managers.

• Liquidity Risk is the risk that a fund will not be able to sell a security at a reasonable price because the security is not traded on a regular basis.

• Market Risk is the risk that the price of a security will fall due to changes in economic, political or market conditions.

• Prepayment Risk means that a fund may lose future interest income when a decline in interest rates causes homeowners to prepay their mortgage loans.

F-16

[GRAPHIC]

THE ALLMERICA FINANCIAL COMPANIES

The Hanover Insurance Company    Citizens Insurance Company of America    Citizens Management Inc.

Opus Investment Management, Inc.    AMGRO, Inc.    Financial Profiles, Inc.

First Allmerica Financial Life Insurance Company    Allmerica Financial Life Insurance and Annuity Company (all states except NY)

440 Lincoln Street, Worcester, Massachusetts 01653

10605 NS (12/03) 04-003

Item 2. Code of Ethics

As of the end of the period covered by this report, the registrant has adopted a code of ethics that applies to the registrant’s principal executive officer and principal financial/principal accounting officer.

Item 3. Audit Committee Financial Expert

The registrant’s Board of Trustees has determined that Gordon Holmes, who is an “independent” Trustee, qualifies as an “audit committee financial expert” (as such term has been defined by SEC regulations).

The SEC has stated that the designation or identification of a person as an audit committee financial expert pursuant to this Item 3 of Form N-CSR does not impose on such person any duties, obligations or liability that are greater than the duties, obligations and liability imposed on such person as a member of the Audit Committee and the Board of Trustees in the absence of such designation or identification.

Item 4. Principal Accountant Fees and Services

	Audit Fees	Types of Services	Percentage of Services Approved by the Audit Committee under Pre-approval Policies and Procedures
2003	$25,850		100%
2002	$23,620		100%
	Audit-Related Fees
2003	$0
2002	$0
	Tax Fees
	$3,300	Tax return review
2003	$3,200		100%
2002			100%
	All Other Fees
2003	$0
2002	$0

All fees disclosed above under the captions “Audit-Related Fees,” “Tax Fees,” and “All Other Fees” represent fees billed for services that were required to be pre-approved, and which were so pre-approved, by the registrant’s Audit Committee in accordance with the Audit Committee’s Policy for Pre-Approval of Services Provided by Independent Auditors.

        % of the hours expended on the independent accountants’ engagement on behalf of the registrant for the fiscal year ended December 31, 2003, were attributable to work performed by persons other than the independent accountants’ full-time, permanent employees. Not applicable

For the last two fiscal years of the registrant, the independent accountants billed aggregate non-audit fees in the following amounts to the registrant and Opus Investment Management, Inc. (“Opus”), the Trust’s investment adviser:

2002	$0
2003	$0

The registrant’s Audit Committee has determined that the provision by the registrant’s independent accountants of non-audit services that were rendered to Opus and that were not pre-approved by the Audit Committee were compatible with maintaining the independence of such accountants.

The Audit Committee has adopted certain policies and procedures for pre-approval of services provided by the independent accountants. On an annual basis, certain types of recurring audit, audit-related and other services are pre-approved by the Committee, including, among other things, the list of required audits and projects presented by the independent accountants; consultation and advisory services related to accounting/reporting and risk management/control matters provided in the normal course of business; and assistance with SEC and other regulatory filings and tax services incurred in the normal course of business. This pre-approval will occur concurrently with the approval of the annual audit fees and will apply to all individual projects meeting the criteria discussed above and which are expected to result in total fees less than $400,000. For individual projects outside the scope of the fiscal year audits and tax return filings expected to be $25,000 or greater, specific pre-approval will be necessary.

Pre-approvals for all other services will occur if and when the need for any such services arises. This pre-approval will be initiated by AFIMS and will be requested from the Chairman or, in the event the Chairman is unavailable, any other member of the Audit Committee. Any services approved by the Chairman, or other Audit Committee member, at any time other than during an Audit Committee meeting will be reported to the full Audit Committee at the next regularly scheduled meeting. Expenses permitted under Rule 2-01(c)(7)(i)(C) of Regulation S-X (the “De Minimis Exception”) will not require pre-approval.

The percentages of expenses that were approved by the Audit Committee in accordance with the De Minimis Exception were as follows: Not applicable

	2003	2002
Audit-Related Fees
Tax Fees
All Other Fees

Item 5. Audit Committee of Listed Registrants

The registrant has a separately-designated standing audit committee established in accordance with Section 3(a)(58)(A) of the Securities Exchange Act of 1934, as amended. The members of the Audit Committee are Gordon Holmes (Chairman), P. Kevin Condron, Jocelyn S. Davis and Attiat F. Ott.

Item 6. Reserved.

Item 7. Disclosure of Proxy Voting Policies and Procedures for Closed-End Management Investment Companies.

Not Applicable. (The registrant invests exclusively in non-voting securities.)

Item 8. Reserved.

Item 9. Controls and Procedures

(a) The registrant’s principal executive and principal financial officers have concluded that, based on their evaluation of the effectiveness of the registrant’s disclosure controls and procedures (as defined in Rule 30a-3(c) under the Investment Company Act of 1940) as of the date within 90 days of the filing date of this report on Form N-CSR, such disclosure controls and procedures provide reasonable assurances that material information relating to the registrant is made known to them by the appropriate persons.

(b) Changes to internal control over financial reporting: Not Applicable

Item 10. Exhibits

(a) Code of ethics that applies to the registrant’s principal executive officer and principal financial/principal accounting officer is attached as Exhibit 99.CODE.

(b)(1) Separate certifications by the registrant’s principal executive officer and principal financial officer, pursuant to Section 302 of the Sarbanes-Oxley Act of 2002 and as required by Rule 30a-2(a) under the Investment Company Act of 1940, are attached hereto as Exhibit 99.CERT.

(2) A certification by the registrant’s principal executive officer and principal financial officer, pursuant to Section 906 of the Sarbanes-Oxley Act of 2002 and as required by Rule 30a-2(b) under the Investment Company Act of 1940 is attached hereto as Exhibit 99.906CERT.

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.

Allmerica Securities Trust
By:	/s/    John P. Kavanaugh
	John P. Kavanaugh President and Chairman

Date: February 23, 2004

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/    John P. Kavanaugh
	John P. Kavanaugh President and Chairman

Date: February 23, 2004

By:	/s/    Paul T. Kane
	Paul T. Kane Assistant Vice President and Treasurer (Principal Accounting Officer and Principal Financial Officer)

Date: February 23, 2004

EX-99.CODE

                                                                      EX-99.CODE

                      Allmerica Investment Trust ("AIT")
                      Allmerica Securities Trust ("AST")

                       FINANCIAL OFFICER CODE OF ETHICS

I. Introduction

The reputation and integrity of AIT and AST (the "Funds") are valuable assets
that are vital to the Funds' success. The Funds' senior financial officers
("SFOs") are responsible for conducting the Funds' business in a manner that
demonstrates a commitment to the highest standards of integrity. The Funds'
SFOs include the principal executive officer, the principal financial officer,
comptroller or principal accounting officer, and any person who performs a
similar function.

The Sarbanes-Oxley Act of 2002 (the "Act") effected sweeping corporate
disclosure and financial reporting reform on public companies, including mutual
funds, to address corporate malfeasance and assure investors that the companies
in which they invest are accurately and completely disclosing financial
information. Under the Act, all public companies (including the Funds) must
either have a code of ethics for their SFOs, or disclose why they do not. The
Act was intended to foster corporate environments which encourage employees to
question and report unethical and potentially illegal business practices. The
Funds have chosen to adopt this Financial Officer Code of Ethics (the "Code")
to encourage its SFOs to act in a manner consistent with the highest principles
of ethical conduct.

II. Purposes of the Code

The purposes of this Code are:

     .    To promote honest and ethical conduct by the Funds' SFOs, including
          the ethical handling of actual or apparent conflicts of interest
          between personal and professional relationships;

     .    To assist the Funds' SFOs in recognizing and avoiding conflicts of
          interest, including disclosing to an appropriate person any material
          transaction or relationship that reasonably could be expected to give
          rise to such a conflict;

     .    To promote full, fair, accurate, timely, and understandable disclosure
          in reports and documents that the Funds file with, or submit to, the
          SEC and in other public communications the Funds make;

     .    To promote Fund compliance with applicable laws, rules and
          regulations;

..    To encourage the prompt internal reporting to an appropriate person of
     violations of this Code; and

..    To establish accountability for adherence to this Code.

III. Questions about this Code

The Funds' Boards of Trustees have designated Donald Wayman to serve as
Compliance Officer for the implementation and administration of the Code.
Questions about this Code should be directed to the Compliance Officer.



IV. Conduct Guidelines

The Funds have adopted the following guidelines under which the Funds' SFOs
must perform their official duties and conduct the business affairs of the
Funds.

     1.   Ethical and honest conduct of paramount importance. The Funds' SFOs
          must act with honesty and integrity and avoid violations of this Code,
          including the avoidance of actual or apparent conflicts of interest
          with the Funds in personal and professional relationships.

     2.   SFOs must disclose material transactions or relationships. The Funds'
          SFOs must disclose to the Compliance Officer any actual or apparent
          conflicts of interest the SFO may have with the Funds that reasonably
          could be expected to give rise to any violations of this Code. Such
          conflicts of interest may arise as a result of material transactions
          or business or personal relationships to which the SFO may be a party.
          If it is not possible to disclose the matter to the Compliance
          Officer, it should be disclosed to the Funds' Chief Financial Officer,
          Chief Executive Officer or another appropriate person. In addition to
          disclosing any actual or apparent conflicts of interest in which an
          SFO is personally involved, the Funds' SFOs have an obligation to
          report any actual or apparent conflicts which they discover or of
          which they otherwise become aware.

     3.   Standards for quality of information shared with Fund service
          providers. The Funds' SFOs must at all times seek to provide
          information to the Funds' service providers (adviser, administrator,
          outside auditor, outside counsel, custodian, etc.) that is accurate,
          complete, objective, relevant, timely and understandable.

     4.   Standards for quality of information included in periodic reports. The
          Funds' SFOs must at all times endeavor to ensure full, fair, timely,
          accurate, and understandable disclosure in the Funds' periodic
          reports.

     5.   Compliance with laws. The Funds' SFOs must comply with the federal
          securities laws and other laws and rules applicable to the Funds, such
          as the Internal Revenue Code.

     6.   Standard of care. The Funds' SFOs must at all times act in good faith
          and with due care, competence and diligence, without misrepresenting
          material facts or allowing their independent judgment to be
          subordinated. The Funds' SFOs must conduct the affairs of the Funds in
          a responsible manner, consistent with this Code.

     7.   Confidentiality of information. The Funds' SFO's must respect and
          protect the confidentiality of information acquired in the course of
          their professional duties, except when authorized by the applicable
          Fund to disclose it or where disclosure is otherwise legally mandated.
          A SFO may not use confidential information acquired in the course of
          his/her work for personal advantage.

     8.   Sharing of information and educational standards. The Funds' SFOs
          should share information with relevant parties to keep them informed
          of the business affairs of the Funds, as appropriate, and maintain
          skills important and relevant to the Funds' needs.

     9.   Promote ethical conduct. The Funds' SFOs should at all times
          proactively promote ethical behavior among peers in their work
          environment.

     10.  Standards for recordkeeping. The Funds' SFOs must at all times
          endeavor to ensure that the Funds' books and records are thoroughly
          and accurately maintained to the best of their knowledge in a manner
          consistent with applicable laws and this Code.



V. Waivers of this Code

A SFO may request a waiver of a provision of this Code by submitting his/her
request in writing to the Compliance Officer for appropriate review. For
example, if a family member works for a service provider that prepares the
Funds' financial statements, a SFO may have a potential conflict of interest in
reviewing those statements and should seek a waiver of this Code to review the
work. An executive officer of the Funds, or another appropriate person (such as
a designated Board or Audit Committee member), will decide whether to grant a
waiver. All waivers of this code must be disclosed to the Funds' shareholders
to the extent required by SEC rules.

VI. Annual Certification

The Funds' SFOs will be asked to certify on an annual basis that they are in
full compliance with this Code. To the extent necessary, the Funds' Compliance
Officer will provide guidance on the conduct required by this Code and the
manner in which violations or suspected violations must be reported and waivers
must be requested.

VII. Reporting Violations

In the event that a SFO discovers or, in good faith, suspects a violation of
this Code, the SFO must immediately report the violation or suspected violation
to the Compliance Officer. The Compliance Officer may, in his or her
discretion, consult with another member of Fund senior management or the Board
in determining how to address the suspected violation. For example, a Code
violation may occur when a Fund periodic report or financial statement omits a
material fact, or is technically accurate but, in the view of the SFO, is
written in a way that obscures its meaning.

When the Funds' service providers perform substantially all of the work
relating to the preparation of the Funds' financial statements and
administration of the day-to-day operations of the Funds, the Funds' SFOs
should make reasonable efforts to monitor the conduct of the service providers
for actions that may be illegal, could be viewed as dishonest or unethical, or
otherwise inconsistent with this Code. In the event that an SFO discovers or,
in good faith, suspects that a Fund service provider may have committed such an
action, the SFO must report the action to the Compliance Officer--even if the
service provider has its own code of ethics for its SFOs or employees.

SFOs who report violations or suspected violations in good faith will not be
subject to retaliation of any kind. Reported violations will be investigated
and addressed promptly and will be treated as confidential to the extent
possible.

VIII. Violations of the Code

Dishonest or unethical conduct or conduct that is illegal will constitute a
violation of this Code, regardless of whether this Code specifically refers to
such particular conduct. A violation of this Code may result in disciplinary
action, up to and including termination of employment. A variety of laws apply
to the Funds and their operations, including the Securities Act of 1933, the
Investment Company Act of 1940, state laws relating to duties owed by Fund
officers, and criminal laws.

Adopted: August 5, 2003

EX-99.CERT

                                                                      EX-99.CERT

                                 CERTIFICATIONS

I, John P. Kavanaugh, certify that:

     1.   I have reviewed this report on Form N-CSR of Allmerica Securities
          Trust;

     2.   Based on my knowledge, this report does not contain any untrue
          statement of a material fact or omit to state a material fact
          necessary to make the statements made, in light of the circumstances
          under which such statements were made, not misleading with respect to
          the period covered by this report;

     3.   Based on my knowledge, the financial statements, and other financial
          information included in this report, fairly present in all material
          respects the financial condition, results of operations, changes in
          net assets, and cash flows (if the financial statements are required
          to include a statement of cash flows) of the registrant as of, and
          for, the periods presented in this report;

     4.   The registrant's other certifying officer(s) and I are responsible for
          establishing and maintaining disclosure controls and procedures (as
          defined in Rule 30a-3(c) under the Investment Company Act of 1940) for
          the registrant and have:

          (a)  Designed such disclosure controls and procedures, or caused such
               disclosure controls and procedures to be designed under our
               supervision, to ensure that material information relating to the
               registrant, including its consolidated subsidiaries, is made
               known to us by others within those entities, particularly during
               the period in which this report is being prepared;

          (b)  Evaluated the effectiveness of the registrant's disclosure
               controls and procedures and presented in this report our
               conclusions about the effectiveness of the disclosure controls
               and procedures, as of a date within 90 days prior to the filing
               date of this report based on such evaluation; and

          (c)  Disclosed in this report any change in the registrant's internal
               control over financial reporting that occurred during the
               registrant's most recent fiscal half-year (the registrant's
               second fiscal half-year in the case of an annual report) that has
               materially affected, or is reasonably likely to materially
               affect, the registrant's internal control over financial
               reporting; and

     5.   The registrant's other certifying officer(s) and I have disclosed to
          the registrant's auditors and the audit committee of the registrant's
          board of directors (or persons performing the equivalent functions):

          (a)  All significant deficiencies and material weaknesses in the
               design or operation of internal control over financial reporting
               which are reasonably likely to adversely affect the registrant's
               ability to record, process, summarize, and report financial
               information; and

          (b)  Any fraud, whether or not material, that involves management or
               other employees who have a significant role in the registrant's
               internal control over financial reporting.

Date: February 23, 2004

/s/ John P. Kavanaugh
- ---------------------
John P. Kavanaugh
President and Chairman



                                    * * * * *
I, Paul T. Kane, certify that:

     1.   I have reviewed this report on Form N-CSR of Allmerica Securities
          Trust;

     2.   Based on my knowledge, this report does not contain any untrue
          statement of a material fact or omit to state a material fact
          necessary to make the statements made, in light of the circumstances
          under which such statements were made, not misleading with respect to
          the period covered by this report;

     3.   Based on my knowledge, the financial statements, and other financial
          information included in this report, fairly present in all material
          respects the financial condition, results of operations, changes in
          net assets, and cash flows (if the financial statements are required
          to include a statement of cash flows) of the registrant as of, and
          for, the periods presented in this report;

     4.   The registrant's other certifying officer(s) and I are responsible for
          establishing and maintaining disclosure controls and procedures (as
          defined in Rule 30a-3(c) under the Investment Company Act of 1940) for
          the registrant and have:

          (a)  Designed such disclosure controls and procedures, or caused such
               disclosure controls and procedures to be designed under our
               supervision, to ensure that material information relating to the
               registrant, including its consolidated subsidiaries, is made
               known to us by others within those entities, particularly during
               the period in which this report is being prepared;

          (b)  Evaluated the effectiveness of the registrant's disclosure
               controls and procedures and presented in this report our
               conclusions about the effectiveness of the disclosure controls
               and procedures, as of a date within 90 days prior to the filing
               date of this report based on such evaluation; and

          (c)  Disclosed in this report any change in the registrant's internal
               control over financial reporting that occurred during the
               registrant's most recent fiscal half-year (the registrant's
               second fiscal half-year in the case of an annual report) that has
               materially affected, or is reasonably likely to materially
               affect, the registrant's internal control over financial
               reporting; and

     5.   The registrant's other certifying officer(s) and I have disclosed to
          the registrant's auditors and the audit committee of the registrant's
          board of directors (or persons performing the equivalent functions):

          (a)  All significant deficiencies and material weaknesses in the
               design or operation of internal control over financial reporting
               which are reasonably likely to adversely affect the registrant's
               ability to record, process, summarize, and report financial
               information; and

          (b)  Any fraud, whether or not material, that involves management or
               other employees who have a significant role in the registrant's
               internal control over financial reporting.

Date: February 23, 2004

/s/ Paul T. Kane
- ----------------
Paul T. Kane
Assistant Vice President and Treasurer
(Principal Accounting Officer and
Principal Financial Officer)

EX-99.906CERT

                                                                   EX-99.906CERT

Certification Pursuant to Section 906 of the Sarbanes-Oxley Act of 2002
(subsection (a) and (b) of section 1350, chapter 63 of title 18, United States
Code)

In connection with the attached Report of Allmerica Securities Trust (the
"Trust") on Form N-CSR to be filed with the Securities and Exchange Commission
for the period ended December 31, 2003 (the "Report"), each of the undersigned
officers of the Trust does hereby certify that, to the best of such officer's
knowledge:

1.   The Report fully complies with the requirements of Section 13(a) or 15(d)
     of the Securities Exchange Act of 1934; and

2.   The information contained in the Report fairly presents, in all material
     respects, the financial condition and results of operations of the Trust as
     of, and for, the periods presented in the Report.

Dated: February 23, 2004

/s/ John P. Kavanaugh
- ---------------------
John P. Kavanaugh
President and Chairman


Dated: February 23, 2004

/s/ Paul T. Kane
- ----------------
Paul T. Kane
Assistant Vice President and Treasurer
(Principal Accounting Officer and
Principal Financial Officer)