Exhibit 21.1

Present Subsidiaries

Entity Name:	State or Jurisdiction Of Incorporation	Percentage of Voting Securities Owned
Teradyne (Asia) Pte., Ltd.	Singapore		100	%*
Teradyne Canada Limited	Canada		100	%
Teradyne de Costa Rica S.A.	Costa Rica		100	%
Teradyne Diagnostic Solutions Ltd.	United Kingdom		100	%*
Teradyne Diagnostic Solutions, Inc.	Delaware		100	%
Teradyne Diagnostic Solutions GmbH	Germany		100	%*
Teradyne GmbH	Germany		100	%*
Teradyne (India) Engineering Private Ltd.	India		100	%*
Teradyne International Holdings B.V.	The Netherlands		100	%
Teradyne Italia SrL	Italy		100	%*
Teradyne K.K.	Japan		100	%
Teradyne Korea Ltd.	Delaware		100	%
Teradyne Limited	United Kingdom		100	%*
Teradyne Malaysia, Ltd	Delaware		100	%
Teradyne Malaysia Sdn. Bhd.	Malaysia		99	%*
Teradyne Philippines Limited	Delaware		100	%
Teradyne SAS	France		100	%
Teradyne (Shanghai) Co., Ltd	Peoples Republic of China		100	%*
Teradyne Taiwan Ltd.	Delaware		100	%
Teradyne Thailand Ltd.	Delaware		100	%
GenRad, LLC	Delaware		100	%
Herco Technology Corp.	California		100	%
P.L.S.T., Inc. (f/k/a Perception Laminates, Inc.)	California		100	%
Eagle Test Systems, Inc.	Delaware		100	%
Eagle Test Systems – Malaysia, Inc.	Delaware		100	%*
Eagle Test Systems (Philippines) LLC	Delaware		100	%*
Eagle Test Systems Italy S.r.l.	Italy		100	%*
Eagle Test Systems Pte. Ltd.	Singapore		100	%*
Nextest Systems Corporation	Delaware		100	%
Nextest Systems (Philippines) Corp.	Philippines		99.9	%*
Nextest Systems (Thailand) Ltd.	Thailand		100	%*

* Indirect subsidiaries whose voting securities are 100% controlled by Teradyne, Inc.