SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT PURSUANT

TO SECTIONS 13 OR 15(d) OF THE

SECURITIES EXCHANGE ACT OF 1934

Date of report (Date of earliest event reported) April 25, 2005.

MYKROLIS CORPORATION

(Exact name of registrant as Specified in its Charter)

Delaware

(State or Other Jurisdiction of Incorporation or Organization)

001-16611	04-3536767
(Commission File Number)	(I.R.S. Employer Identification No.)

129 Concord Road, Billerica, MA	01821
(Address of principal executive offices)	(Zip Code)

(978) 436-6500

(Registrant’s telephone number, including area code)

N/A

(Former Name or Former Address, if Changed Since Last Report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2.):

¨ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

¨ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

¨ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

¨ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Section 1. Registrant’s Business and Operations

Item 1.01 Entry into Material Definitive Agreement

Effective April 25, 2005, the cash compensation payable to the directors of Mykrolis Corporation was changed to increase the annual retainer to $50,000 from its prior level of $25,000, payable in advance and to eliminate all per meeting fees. There is no change in the annual retainer for the Chairman of the Audit & Finance Committee at $8,000 or for the Chairman of the Management Development & Compensation Committee at $5,000; each of which is in addition to the directors annual retainer.

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SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized.

	MYKROLIS CORPORATION
Dated: April 28, 2005	By	/s/ Peter W. Walcott
		Peter W. Walcott,
		Vice President & General Counsel

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