<SEC-DOCUMENT>0001258897-16-002921-index.html : 20160209
<SEC-HEADER>0001258897-16-002921.hdr.sgml : 20160209
<ACCEPTANCE-DATETIME>20160209162231
ACCESSION NUMBER:		0001258897-16-002921
CONFORMED SUBMISSION TYPE:	SC 13G/A
PUBLIC DOCUMENT COUNT:		1
FILED AS OF DATE:		20160209
DATE AS OF CHANGE:		20160209

SUBJECT COMPANY:	

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			MKS INSTRUMENTS INC
		CENTRAL INDEX KEY:			0001049502
		STANDARD INDUSTRIAL CLASSIFICATION:	INDUSTRIAL INSTRUMENTS FOR MEASUREMENT, DISPLAY, AND CONTROL [3823]
		IRS NUMBER:				042277512
		STATE OF INCORPORATION:			MA
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		SC 13G/A
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	005-58011
		FILM NUMBER:		161400034

	BUSINESS ADDRESS:	
		STREET 1:		2 TECH DRIVE
		STREET 2:		SUITE 201
		CITY:			ANDOVER
		STATE:			MA
		ZIP:			01810
		BUSINESS PHONE:		978-645-5500

	MAIL ADDRESS:	
		STREET 1:		2 TECH DRIVE
		STREET 2:		SUITE 201
		CITY:			ANDOVER
		STATE:			MA
		ZIP:			01810

FILED BY:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			DIMENSIONAL FUND ADVISORS LP
		CENTRAL INDEX KEY:			0000354204
		STANDARD INDUSTRIAL CLASSIFICATION:	UNKNOWN SIC - 0000 [0000]
		IRS NUMBER:				222370029
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		SC 13G/A

	BUSINESS ADDRESS:	
		STREET 1:		6300 BEE CAVE ROAD
		STREET 2:		BUILDING ONE
		CITY:			AUSTIN
		STATE:			TX
		ZIP:			78746
		BUSINESS PHONE:		(512) 306-7400

	MAIL ADDRESS:	
		STREET 1:		6300 BEE CAVE ROAD
		STREET 2:		BUILDING ONE
		CITY:			AUSTIN
		STATE:			TX
		ZIP:			78746

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	DIMENSIONAL FUND ADVISORS INC
		DATE OF NAME CHANGE:	19920929
</SEC-HEADER>
<DOCUMENT>
<TYPE>SC 13G/A
<SEQUENCE>1
<FILENAME>rrd355.htm
<DESCRIPTION>SCHEDULE 13G/A
<TEXT>
Document 1 - file: rrd355.htm

</DOCUMENT>
</SEC-DOCUMENT>