As filed with the Securities and Exchange Commission on May 16, 2018.
1933 Act Registration No.  333-43300
1940 Act Registration No.  811-10041
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. 42			[X]
and/or
REGISTRATION STATEMENT UNDER THE INVESTMENT COMPANY ACT OF 1940			[X]
Amendment No. 43
JNL INVESTORS SERIES TRUST
(Exact Name of Registrant as Specified in Charter)
1 Corporate Way, Lansing, Michigan 48951
(Address of Principal Executive Offices) (Zip Code)
Registrant’s Telephone Number, including Area Code: (517) 381-5500
225 West Wacker Drive, Chicago, Illinois 60606
(Mailing Address)
with a copy to:
Susan S. Rhee, Esq.		Ropes & Gray LLP
JNL Investors Series Trust		32nd Floor
Vice President, Chief Legal Officer & Secretary		191 North Wacker Drive
1 Corporate Way		Chicago, Illinois  60606
Lansing, Michigan 48951		Attn:  Paulita A. Pike, Esq.
(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 ____________ pursuant to paragraph (b)
[   ]	60 days after filing pursuant to paragraph (a)(1)
[   ]	on ____________ pursuant to paragraph (a)(1)
[   ]	75 days after filing pursuant to paragraph (a)(2)
[   ]	on (date) pursuant to paragraph (a)(2) of Rule 485
[   ]	This post-effective amendment designates a new effective date for a previously filed post-effective amendment.
Part C.
This Post-Effective Amendment No. 42 is filed for the sole purpose of submitting the XBRL exhibit for the risk/return summary first provided in Post-Effective Amendment No. 40 to the Trust’s Registration Statement.

EXHIBIT LIST
Exhibit Number	Exhibit Description
101.INS	XBRL Instance Document
101.SCH	XBRL Taxonomy Extension Schema Document
101.CAL	XBRL Taxonomy Extension Calculation Linkbase
101.LAB	XBRL Taxonomy Extension Labels Linkbase
101.PRE	XBRL Taxonomy Extension Presentation Linkbase
101.DEF	XBRL Taxonomy Extension Definition Linkbase

SIGNATURES
Pursuant to the requirements of the Securities Act and the Investment Company Act, the Trust certifies that it meets all of the requirements for effectiveness of this Post-Effective Amendment under rule 485(b) under the Securities Act and has duly caused this Post-Effective Amendment to be signed on its behalf by the undersigned, duly authorized, in the City of Lansing and the State of Michigan on the 16th day of May, 2018.
JNL INVESTORS SERIES TRUST
/s/ Susan S. Rhee
Susan S. Rhee
Vice President, Chief Legal Officer, and Secretary
Pursuant to the requirements of the Securities Act, this Post-Effective Amendment has been signed below by the following persons in the capacities and on the date indicated.
/s/ Susan S. Rhee *	May 16, 2018
Eric O. Anyah
Trustee
/s/ Susan S. Rhee *	May 16, 2018
Michael Bouchard
Trustee
/s/ Susan S. Rhee *	May 16, 2018
Ellen Carnahan
Trustee
/s/ Susan S. Rhee *	May 16, 2018
William Crowley
Trustee
/s/ Susan S. Rhee *	May 16, 2018
Michelle Engler
Trustee
/s/ Susan S. Rhee *	May 16, 2018
John W. Gillespie
Trustee
/s/ Susan S. Rhee *	May 16, 2018
William R. Rybak
Trustee
/s/ Susan S. Rhee *	May 16, 2018
Mark S. Wehrle
Trustee
/s/ Susan S. Rhee *	May 16, 2018
Edward C. Wood
Trustee
/s/ Susan S. Rhee *	May 16, 2018
Patricia A. Woodworth
Trustee
/s/ Susan S. Rhee *	May 16, 2018
Mark D. Nerud
Trustee, President and Chief Executive Officer (Principal Executive Officer)
/s/ Susan S. Rhee  *	May 16, 2018
Daniel W. Koors
Vice President, Treasurer and Chief Financial Officer (Principal Financial Officer)
* By Susan S. Rhee, Attorney In Fact