File No. 33-27172

811-5719

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM N-1A

REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933[X]

Pre-Effective Amendment No.[__]

Post-Effective Amendment No. 29[X]

and/or

REGISTRATION STATEMENT UNDER THE INVESTMENT COMPANY ACT OF 1940[X]

Amendment No. 29[X]

(Check appropriate box or boxes.)

Dreyfus Stock Index Fund, Inc.

(Exact Name of Registrant as Specified in Charter)

c/o The Dreyfus Corporation

200 Park Avenue, New York, New York 10166

(Address of Principal Executive Offices) (Zip Code)

Registrant's Telephone Number, including Area Code: (212) 922-6000

Michael A. Rosenberg, Esq.

200 Park Avenue

New York, New York 10166

(Name and Address of Agent for Service)

Approximate Date of Proposed Public Offering April 30, 2011

It is proposed that this filing will become effective (check appropriate box)

__immediately upon filing pursuant to paragraph (b)

X on April 30, 2011 pursuant to paragraph (b)

____ after filing pursuant to paragraph (a)(1)

__on (date) pursuant to paragraph (a)(1)

____ days after filing pursuant to paragraph (a)(2)

__on (date) pursuant to paragraph (a)(2) of Rule 485

If appropriate, check the following box:

__this post-effective amendment designates a new effective date for a previously filed post-effective amendment.

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, the Registrant, Dreyfus Stock Index Fund, Inc., certifies that it meets all of the requirements for effectiveness of this Amendment to the Registration Statement pursuant to Rule 485(b) under the Securities Act of 1933 and has duly caused this Amendment to the Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of New York, and State of New York on the 27th of April 2011.

Dreyfus Stock Index Fund, Inc.

BY:	/s/ Bradley J. Skapyak*
	Bradley J. Skapyak, PRESIDENT

Pursuant to the requirements of the Securities Act of 1933, this Amendment to the Registration Statement has been signed below by the following persons in the capacities and on the date indicated.

Signatures	Title	Date
/s/ Bradley J. Skapyak*	President (Principal Executive Officer)	04/27/2011
Bradley J. Skapyak
/s/ James Windels*	Treasurer (Principal Financial and Accounting Officer)	04/27/2011
James Windels
/s/ Joseph S. DiMartino*	Chairman of the Board	04/27/2011
Joseph S. DiMartino
/s/ Peggy C. Davis*	Board Member	04/27/2011
Peggy C. Davis
/s/ David P. Feldman*	Board Member	04/27/2011
David P. Feldman
/s/ Ehud Houminer*	Board Member	04/27/2011
Ehud Houminer
/s/ Martin Peretz*	Board Member	04/27/2011
Martin Peretz

*BY:	/s/ Michael A. Rosenberg
	Michael A. Rosenberg Attorney-in-Fact

INDEX OF EXHIBITS

_________________________

Exhibits

EX-101.INS – Instance Document.

EX-101.SCH – Taxonomy.

EX-101.CAL – Calculation Linkbase.

EX-101.DEF – Definition Linkbase.

EX-101.LAB – Labels Linkbase.

EX-101.PRE – Presentation Linkbase.