As filed with the Securities and Exchange Commission on September 19, 2013

Registration No. 333-89661; 811-09645

UNITED STATES

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. 124

x

REGISTRATION STATEMENT

UNDER

THE INVESTMENT COMPANY ACT OF 1940

x

Amendment No. 125

(Check appropriate box or boxes)

COLUMBIA FUNDS SERIES TRUST

(Exact Name of Registrant as specified in Charter)

50606 Ameriprise Financial Center

Minneapolis, MN 55474

(Address of Principal Executive Offices, including Zip Code)

Registrant’s Telephone Number, including Area Code: (800) 345-6611

Christopher O. Petersen, Esq.

c/o Columbia Management Investment Advisers, LLC

225 Franklin Street

Boston, MA 02110

(Name and Address of Agent for Service)

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.

This Post-Effective Amendment relates solely to the Registrant’s Columbia California Intermediate Municipal Bond Fund, Columbia Georgia Intermediate Municipal Bond Fund, Columbia Maryland Intermediate Municipal Bond Fund, Columbia North Carolina Intermediate Municipal Bond Fund, Columbia Short Term Municipal Bond Fund, Columbia South Carolina Intermediate Municipal Bond Fund and Columbia Virginia Intermediate Municipal Bond Fund series. Information contained in the Registrant’s Statement relating to any other series of the Registrant is neither amended nor superseded hereby.

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933 and the Investment Company Act of 1940, the Registrant, Columbia Funds Series Trust, certifies that it meets all the requirements for effectiveness of this Registration Statement under Rule 485(b) under the Securities Act of 1933 and has duly caused this Registration Statement to be signed on its behalf by the undersigned, duly authorized, in the City of Boston, and The Commonwealth of Massachusetts on the 19th day of September, 2013.

COLUMBIA FUNDS SERIES TRUST
By:	/s/ J. Kevin Connaughton
Name: Title:	J. Kevin Connaughton President

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

SIGNATURES	TITLE	DATE
/s/ J. Kevin Connaughton J. Kevin Connaughton	President (Principal Executive Officer)	September 19, 2013
/s/ Michael G. Clarke Michael G. Clarke	Chief Financial Officer (Principal Financial Officer)	September 19, 2013
/s/ Joseph F. DiMaria Joseph F. DiMaria	Chief Accounting Officer (Principal Accounting Officer)	September 19, 2013
/s/ Stephen R. Lewis, Jr.* Stephen R. Lewis, Jr.	Chairman of the Board	September 19, 2013
/s/ Kathleen A. Blatz* Kathleen A. Blatz	Trustee	September 19, 2013
/s/ Edward J. Boudreau, Jr.* Edward J. Boudreau, Jr.	Trustee	September 19, 2013
/s/ Pamela G. Carlton* Pamela G. Carlton	Trustee	September 19, 2013
/s/ William P. Carmichael* William P. Carmichael	Trustee	September 19, 2013

/s/ Patricia M. Flynn* Patricia M. Flynn	Trustee	September 19, 2013
/s/ William A. Hawkins* William A. Hawkins	Trustee	September 19, 2013
/s/ R. Glenn Hilliard* R. Glenn Hilliard	Trustee	September 19, 2013
/s/ Catherine James Paglia* Catherine James Paglia	Trustee	September 19, 2013
/s/ Leroy C. Richie* Leroy C. Richie	Trustee	September 19, 2013
/s/ Anthony M. Santomero* Anthony M. Santomero	Trustee	September 19, 2013
/s/ Minor M. Shaw* Minor M. Shaw	Trustee	September 19, 2013
/s/ Alison Taunton-Rigby* Alison Taunton-Rigby	Trustee	September 19, 2013
/s/ William F. Truscott* William F. Truscott	Trustee	September 19, 2013

*By:	/s/ Ryan C. Larrenaga
	Ryan C. Larrenaga** Attorney-in-Fact September 19, 2013

** Executed by Ryan C. Larrenaga on behalf of each of the Trustees pursuant to a Power of Attorney dated April 17, 2013 and incorporated by reference to Post-Effective Amendment No. 116 to the Registration Statement of the Registrant on Form N-1A, filed with the Commission on May 2, 2013.

EXHIBIT INDEX

Exhibit No.	Description
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