    <SEC-DOCUMENT>0001193125-22-091844-index.html : 20220331
    <SEC-HEADER>0001193125-22-091844.hdr.sgml : 20220331
    <ACCEPTANCE-DATETIME>20220331162402
    ACCESSION NUMBER:		0001193125-22-091844
    CONFORMED SUBMISSION TYPE:	DEFA14A
    PUBLIC DOCUMENT COUNT:		3
    FILED AS OF DATE:		20220331
    DATE AS OF CHANGE:		20220331

    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:		DEFA14A
    		SEC ACT:		1934 Act
    		SEC FILE NUMBER:	000-23621
    		FILM NUMBER:		22792917

    	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>DEFA14A
    <SEQUENCE>1
    <FILENAME>d302172ddefa14a.htm
    <DESCRIPTION>NOTICE AND ACCESS
    <TEXT>
    Document 1 - file: d302172ddefa14a.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>2
    <FILENAME>g302172g00k04.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 2 - file: g302172g00k04.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>3
    <FILENAME>g302172g00k05.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 3 - file: g302172g00k05.jpg

    </DOCUMENT>
    </SEC-DOCUMENT>