MKS INC — Director's Dealing 2010

May 5, 2010

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: MKS INSTRUMENTS INC (MKSI)
CIK: 0001049502
Period of Report: 2010-05-03

Reporting Person: VALENTE LOUIS P (Director)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2010-05-03	Common Stock	A	6000	—	Acquired	10000	Direct

Footnotes

F1: This RSU grant fully vests on the day prior to the first annual meeting of shareholders following the date of grant (or if no such meeting is held within 13 months after the date of grant, on the 13 month anniversary of the date of grant).