UNITED STATES
SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d)
of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported):
May 11, 2007

CERIDIAN CORPORATION
(Exact name of registrant as specified in its charter)

3311 East Old Shakopee Road, Minneapolis, Minnesota  55425
(Address of principal executive offices)        (Zip code)

Registrant’s telephone number, including area code:      (952) 853-8100

         No Change         
(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:

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

     [X] 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))

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Item 8.01.          Other Events

On March 7, 2007, Pershing Square, L.P., Pershing Square II, L.P. and Pershing Square International, Ltd. (“Pershing Square”) filed an action against Ceridian Corporation (the “Company”) in the Delaware Chancery Court (the “Court”), under Section 220 of the Delaware General Corporation Law, seeking to compel the Company to disclose two letters written by executives of the Company to the Company’s board of directors.  On May 11, 2007, the Court issued a written opinion denying Pershing Square’s request and setting forth the reasons for its decision.  The written opinion of the Court is attached hereto as Exhibit 99.1 and incorporated herein by reference.

ADDITIONAL INFORMATION AND WHERE TO FIND IT

In connection with its 2007 Annual Meeting, Ceridian will be filing a proxy statement, White Proxy Card and other materials with the SEC. WE URGE INVESTORS TO READ THE PROXY STATEMENT AND THESE OTHER MATERIALS CAREFULLY WHEN THEY BECOME AVAILABLE BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION ABOUT CERIDIAN AND THE MATTERS TO BE CONSIDERED AT ITS ANNUAL MEETING. Investors may contact MacKenzie Partners, Inc., the company's proxy advisor, for the 2007 Annual Meeting, at 800-322-2885 or by email at ceridianproxy@mackenziepartners.com.  Investors may also obtain a free copy of the proxy statement and other relevant documents when they become available as well as other materials filed with the SEC concerning Ceridian at the SEC's website at http://www.sec.gov.  Free copies of Ceridian's SEC filings are also available on Ceridian's website at http://www.ceridian.com.  These materials and other documents may also be obtained for free from: Ceridian Corporation, 3311 East Old Shakopee Road, Minneapolis, Minnesota 55425, Attn: Investor Relations.

PARTICIPANTS IN THE SOLICITATION

Ceridian and its officers and directors may be deemed, under SEC rules, to be participants in the solicitation of proxies from Ceridian's stockholders with respect to the matters to be considered at Ceridian's 2007 Annual Meeting. Information regarding the officers and directors of Ceridian is included in its definitive proxy statement for its 2006 Annual Meeting filed with the SEC on March 27, 2006, and on Ceridian's website at http://www.ceridian.com.  More detailed information regarding the identity of potential participants, and their direct or indirect interests, by securities, holdings or otherwise, will be set forth in the proxy statement and other materials to be filed with the SEC in connection with Ceridian's 2007 Annual Meeting.

Item 9.01.          Financial Statements and Exhibits.

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SIGNATURES

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 hereunto duly authorized.

Dated: May 14, 2007

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