Registration Nos. 2-98326

811-04323

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, DC 20549

FORM N-1A

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933	☐
Pre-Effective Amendment No.	☐
Post-Effective Amendment No. 135	☒

and/or

REGISTRATION STATEMENT

UNDER

THE INVESTMENT COMPANY ACT OF 1940	☐
Amendment No. 136 (Check appropriate box or boxes.)	☒

NATIXIS FUNDS TRUST I

(Exact Name of Registrant as Specified in Charter)

399 Boylston Street, Boston, Massachusetts	02116
(Address of principal executive offices)	(Zip Code)

Registrant’s Telephone Number, including Area Code (617) 449-2822

Copy to:

Russell Kane, Esq. NGAM Distribution, L.P. 399 Boylston Street Boston, Massachusetts 02116	John M. Loder, Esq. Ropes & Gray 800 Boylston Street Boston, Massachusetts 02116
(Name and Address of Agent for Service)

Approximate Date of Proposed Public Offering

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

☒ 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.

NATIXIS FUNDS TRUST I

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, as amended, and the Investment Company Act of 1940, as amended, the Registrant certifies that it meets all of the requirements for effectiveness of this Post-Effective Amendment to its Registration Statement under Rule 485(b) under the Securities Act of 1933, as amended, and has duly caused this Post-Effective Amendment to its 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 22^nd day of May, 2017.

NATIXIS FUNDS TRUST I
By:	/s/ David L. Giunta
	David L. Giunta
	President and Chief Executive Officer

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

Signature	Title	Date
/s/ David L. Giunta	President and Chief
David L. Giunta	Executive Officer and Trustee	May 22, 2017
/s/ Michael C. Kardok
Michael C. Kardok	Treasurer	May 22, 2017
Kevin P. Charleston*
Kevin P. Charleston	Trustee	May 22, 2017
Kenneth A. Drucker*
Kenneth A. Drucker	Trustee, Chairperson of the Board	May 22, 2017
Edmond J. English*
Edmond J. English	Trustee	May 22, 2017
Richard A. Goglia*
Richard A. Goglia	Trustee	May 22, 2017
Wendell J. Knox*
Wendell J. Knox	Trustee	May 22, 2017
Martin T. Meehan*
Martin T. Meehan	Trustee	May 22, 2017
Sandra O. Moose*
Sandra O. Moose	Trustee	May 22, 2017
James P. Palermo*
James P. Palermo	Trustee	May 22, 2017
Erik Sirri*
Erik Sirri	Trustee	May 22, 2017
Peter Smail*
Peter Smail	Trustee	May 22, 2017
Cynthia L. Walker*
Cynthia L. Walker	Trustee	May 22, 2017

*By:	/s/ Russell Kane
	Russell Kane
	Attorney-In-Fact1
	May 22, 2017

¹  Powers of Attorney for Kevin P. Charleston, Kenneth A. Drucker, Edmond J. English, Richard A. Goglia, Wendell J. Knox, Martin T. Meehan, Sandra O. Moose, James P. Palermo, Erik R. Sirri, Peter J. Smail and Cynthia L. Walker is incorporated by reference to exhibit (p)(1) to PEA No. 126 to the Registration Statement filed on December 9, 2016.

Natixis Funds Trust I

Exhibit Index

Exhibits for Item 28 of Form N-1A

Exhibit	Exhibit 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