    <SEC-DOCUMENT>0000937556-23-000129-index.html : 20230601
    <SEC-HEADER>0000937556-23-000129.hdr.sgml : 20230601
    <ACCEPTANCE-DATETIME>20230601090113
    ACCESSION NUMBER:		0000937556-23-000129
    CONFORMED SUBMISSION TYPE:	DEFA14A
    PUBLIC DOCUMENT COUNT:		8
    FILED AS OF DATE:		20230601
    DATE AS OF CHANGE:		20230601

    FILER:

    	COMPANY DATA:
    		COMPANY CONFORMED NAME:			MASIMO CORP
    		CENTRAL INDEX KEY:			0000937556
    		STANDARD INDUSTRIAL CLASSIFICATION:	ELECTROMEDICAL & ELECTROTHERAPEUTIC APPARATUS [3845]
    		IRS NUMBER:				330368882
    		STATE OF INCORPORATION:			DE
    		FISCAL YEAR END:			1231

    	FILING VALUES:
    		FORM TYPE:		DEFA14A
    		SEC ACT:		1934 Act
    		SEC FILE NUMBER:	001-33642
    		FILM NUMBER:		23983182

    	BUSINESS ADDRESS:
    		STREET 1:		52 DISCOVERY
    		CITY:			IRVINE
    		STATE:			CA
    		ZIP:			92618
    		BUSINESS PHONE:		949-297-7000

    	MAIL ADDRESS:
    		STREET 1:		52 DISCOVERY
    		CITY:			IRVINE
    		STATE:			CA
    		ZIP:			92618
    </SEC-HEADER>
    <DOCUMENT>
    <TYPE>DEFA14A
    <SEQUENCE>1
    <FILENAME>masi-20230530xdefa14a.htm
    <DESCRIPTION>DEFA14A
    <TEXT>
    Document 1 - file: masi-20230530xdefa14a.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>2
    <FILENAME>masimologo300x1a05.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 2 - file: masimologo300x1a05.jpg

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    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>3
    <FILENAME>figure1.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 3 - file: figure1.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>4
    <FILENAME>figure2_53023.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 4 - file: figure2_53023.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>5
    <FILENAME>figure3.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 5 - file: figure3.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>6
    <FILENAME>figure4.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 6 - file: figure4.jpg

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    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>7
    <FILENAME>figure5_53023.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 7 - file: figure5_53023.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>8
    <FILENAME>figure6.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 8 - file: figure6.jpg

    </DOCUMENT>
    </SEC-DOCUMENT>