<SEC-DOCUMENT>0000906304-17-000133-index.html : 20170201
<SEC-HEADER>0000906304-17-000133.hdr.sgml : 20170201
<ACCEPTANCE-DATETIME>20170201130102
ACCESSION NUMBER:		0000906304-17-000133
CONFORMED SUBMISSION TYPE:	SC 13G/A
PUBLIC DOCUMENT COUNT:		1
FILED AS OF DATE:		20170201
DATE AS OF CHANGE:		20170201

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:		17564024

	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:			ROYCE & ASSOCIATES LP
		CENTRAL INDEX KEY:			0000906304
		IRS NUMBER:				522343049
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			0331

	FILING VALUES:
		FORM TYPE:		SC 13G/A

	BUSINESS ADDRESS:	
		STREET 1:		745 FIFTH AVENUE
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10151
		BUSINESS PHONE:		212-508-4500

	MAIL ADDRESS:	
		STREET 1:		745 FIFTH AVENUE
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10151

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	ROYCE & ASSOCIATES LLC
		DATE OF NAME CHANGE:	20020507

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	ROYCE & ASSOCIATES INC /NY
		DATE OF NAME CHANGE:	19990329

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	QUEST ADVISORY CORP/NY
		DATE OF NAME CHANGE:	19970805
</SEC-HEADER>
<DOCUMENT>
<TYPE>SC 13G/A
<SEQUENCE>1
<FILENAME>mksi11.txt
<TEXT>
Document 1 - file: mksi11.txt

</DOCUMENT>
</SEC-DOCUMENT>