As filed with the Securities and Exchange Commission on March 9, 2011

Securities Act File No. 333-56203

Investment Company Act File No. 811-08797

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. 18	x
and/or REGISTRATION STATEMENT UNDER THE INVESTMENT COMPANY ACT OF 1940	x
Amendment No. 62	x

(Check appropriate box or boxes)

BLACKROCK INTERNATIONAL FUND OF BLACKROCK SERIES, INC.

(Exact Name of Registrant as Specified in Charter)

100 Bellevue Parkway, Wilmington, Delaware 19809

(Address of Principal Executive Office)

Registrant’s Telephone Number, including Area Code (800) 441-7762

John M. Perlowski

BlackRock International Fund of BlackRock Series, Inc.

55 East 52^nd Street

New York, New York 10055

United States of America

(Name and Address of Agent for Service)

Copies to:

Counsel for the Fund:
Frank P. Bruno, Esq.	Ira P. Shapiro, Esq.
Sidley Austin LLP	BlackRock Advisors, LLC
787 Seventh Avenue	55 East 52nd Street
New York, New York 10019-6018	New York, New York 10055

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

x immediately upon filing pursuant to paragraph (b)

¨ on (date) pursuant to paragraph (b)

¨ 60 days after filing pursuant to paragraph (a)(1)

¨ on (date) pursuant to paragraph (a)(1)

¨ 75 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.

Title of Securities Being Registered: Shares of Common Stock.

BlackRock Master LLC has also executed this Registration Statement.

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933 and the Investment Company Act of 1940, the Registrant certifies that it meets all of the requirements for effectiveness of this Post-Effective Amendment to the Registration Statement pursuant to Rule 485(b) under the Securities Act and has duly caused this Post-Effective Amendment to its Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of New York and the State of New York on March 9, 2011.

BLACKROCK INTERNATIONAL FUND OF BLACKROCK SERIES, INC.
(Registrant)
By:	/S/ JOHN M. PERLOWSKI
	(John M. Perlowski,
	President and Chief Executive Officer)

Pursuant to the requirements of the Securities Act, this Post-Effective Amendment to its Registration Statement has been signed below by the following persons in the capacities and on the dates indicated:

Signature	Title	Date
/S/ JOHN M. PERLOWSKI	President and Chief Executive Officer (Principal Executive Officer)	March 9, 2011
(John M. Perlowski)
/S/ NEAL J. ANDREWS	Chief Financial Officer (Principal Financial and Accounting Officer)	March 9, 2011
(Neal J. Andrews)
DAVID O. BEIM*	Director
(David O. Beim)
RONALD W. FORBES*	Director
(Ronald W. Forbes)
DR. MATINA S. HORNER*	Director
(Dr. Matina S. Horner)
RODNEY D. JOHNSON*	Director
(Rodney D. Johnson)
HERBERT I. LONDON*	Director
(Herbert I. London)
CYNTHIA A. MONTGOMERY*	Director
(Cynthia A. Montgomery)
JOSEPH P. PLATT*	Director
(Joseph P. Platt)
ROBERT C. ROBB, JR.*	Director
(Robert C. Robb, Jr.)
TOBY ROSENBLATT*	Director
(Toby Rosenblatt)

	KENNETH L. URISH*	Director
	(Kenneth L. Urish)
	FREDERICK W. WINTER*	Director
	(Frederick W. Winter)
	RICHARD S. DAVIS*	Director
	(Richard S. Davis)
	HENRY GABBAY*	Director
	(Henry Gabbay)
*By:	/S/ BEN ARCHIBALD		March 9, 2011
	Ben Archibald (Attorney-In-Fact)

SIGNATURES

BlackRock Master LLC has duly caused this Post-Effective Amendment to the Registration Statement of BlackRock International Fund of BlackRock Series, Inc. to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of New York and the State of New York on March 9, 2011.

BLACKROCK MASTER LLC
By:	/s/ John M. Perlowski
	(John M. Perlowski,
	President and Chief Executive Officer)

Pursuant to the requirements of the Securities Act of 1933, this Post-Effective Amendment to the Registration Statement of BlackRock International Fund or BlackRock Series, Inc. has been signed below by the following persons in the capacities and on the dates indicated:

Signature	Title	Date
/s/ John M. Perlowski	President and Chief Executive Officer (Principal Executive Officer)	March 9, 2011
John M. Perlowski
/s/ Neal J. Andrews	Chief Financial Officer (Principal Financial and Accounting Officer)	March 9, 2011
Neal J. Andrews
David O. Beim*	Director
David O. Beim
Ronald W. Forbes*	Director
Ronald W. Forbes
Dr. Matina S. Horner*	Director
Dr. Matina S. Horner
Rodney D. Johnson*	Director
Rodney D. Johnson
Herbert I. London*	Director
Herbert I. London
Cynthia A. Montgomery*	Director
Cynthia A. Montgomery
Joseph P. Platt*	Director
Joseph P. Platt
Robert C. Robb, Jr.*	Director
Robert C. Robb, Jr.
Toby Rosenblatt*	Director
Toby Rosenblatt

	Kenneth L. Urish*	Director
	Kenneth L. Urish
	Frederick W. Winter*	Director
	Frederick W. Winter
	Richard S. Davis*	Director
	Richard S. Davis
	Henry Gabbay*	Director
	Henry Gabbay
*By:	/S/ BEN ARCHIBALD		March 9, 2011
	Ben Archibald (Attorney-In-Fact)

EXHIBIT INDEX

Index No.	Description of Exhibit
EX-101.INS	XBRL Instance Document
EX-101.SCH	XBRL Taxonomy Extension Schema Document
EX-101.CAL	XBRL Taxonomy Extension Calculation Linkbase
EX-101.DEF	XBRL Taxonomy Extension Definition Linkbase
EX-101.LAB	XBRL Taxonomy Extension Labels Linkbase
EX-101.PRE	XBRL Taxonomy Extension Presentation Linkbase