<SEC-DOCUMENT>0001193125-19-089174-index.html : 20190328
<SEC-HEADER>0001193125-19-089174.hdr.sgml : 20190328
<ACCEPTANCE-DATETIME>20190328061003
ACCESSION NUMBER:		0001193125-19-089174
CONFORMED SUBMISSION TYPE:	DEF 14A
PUBLIC DOCUMENT COUNT:		5
CONFORMED PERIOD OF REPORT:	20190508
FILED AS OF DATE:		20190328
DATE AS OF CHANGE:		20190328
EFFECTIVENESS DATE:		20190328

FILER:

	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:		DEF 14A
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-23621
		FILM NUMBER:		19709855

	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
</SEC-HEADER>
<DOCUMENT>
<TYPE>DEF 14A
<SEQUENCE>1
<FILENAME>d676843ddef14a.htm
<DESCRIPTION>DEFINITIVE PROXY STATEMENT
<TEXT>
Document 1 - file: d676843ddef14a.htm

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>2
<FILENAME>g676843g31n98.jpg
<DESCRIPTION>GRAPHIC
<TEXT>
Document 2 - file: g676843g31n98.jpg

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>3
<FILENAME>g676843g31o97.jpg
<DESCRIPTION>GRAPHIC
<TEXT>
Document 3 - file: g676843g31o97.jpg

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>4
<FILENAME>g676843g37g92.jpg
<DESCRIPTION>GRAPHIC
<TEXT>
Document 4 - file: g676843g37g92.jpg

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>5
<FILENAME>g676843pcpg02.jpg
<DESCRIPTION>GRAPHIC
<TEXT>
Document 5 - file: g676843pcpg02.jpg

</DOCUMENT>
</SEC-DOCUMENT>