MKS INC — Director's Dealing 2010

Sep 21, 2010

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: MKS INSTRUMENTS INC (MKSI)
CIK: 0001049502
Period of Report: 2010-09-17

Reporting Person: COLELLA GERARD G (VP, Chief Operating Officer)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2010-09-17	Common Stock	M	1000	—	Acquired	1023	Direct
2010-09-17	Common Stock	F	318	$18.59	Disposed	705	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2010-09-17	Restricted Stock Unit	$	M	1000	Disposed		Common Stock (1000)	Direct

Footnotes

F1: This transaction was effected pursuant to a Rule 10b5-1 trading plan previously adopted by the reporting person.

F2: Each restricted stock unit represents the contingent right to receive one share of common stock of MKS Instruments, Inc.

F3: The RSUs vest in equal annual installments over three years.