May 7, 2007

Trust Assigned AAAf Fund Credit Rating by Standard & Poor's

MINNEAPOLIS, May 7, 2007 - Ceridian Corporation (NYSE: CEN) today announced that the Ceridian client funds trust for its payroll, tax filing and other customers in its U.S. Human Resource Solutions business has been assigned a AAAf fund credit rating by Standard & Poor's Corporation (S&P).

"I am extremely pleased to announce that Standard & Poor's has assigned its highest fund credit rating to our client funds trust," said Kathryn V. Marinello, president and chief executive officer of Ceridian Corporation.

"Our clients trust us to handle their funds, and we take that responsibility seriously," Marinello continued. "We use a trust to hold client funds, which serves to keep our clients' funds completely separate from our corporate funds and to protect those funds from claims by outsiders. The assignment of S&P's highest fund credit rating to these trust investments provides further assurance to our clients that their funds are invested according to the highest standards of safety and soundness. We are committed to maintaining these high standards for the benefit of our clients going forward."

Ceridian Corporation (www.ceridian.com) is an information services company serving businesses and employees in the United States, Canada and Europe. Ceridian is one of the top human resources outsourcing companies in each of its markets, and offers a broad range of human resource services, including payroll, benefits administration, tax compliance, HR information systems and Employee Assistance Program (EAP) and work-life solutions. Through its Comdata subsidiary, Ceridian is a major payment processor and issuer of credit cards, debit cards and stored value cards, primarily for the trucking and retail industries in the United States.

This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. The statements regarding Ceridian Corporation contained in this release that are not historical in nature, particularly those that utilize terminology such as "may," "will," "should," "likely," "expects," "anticipates," "estimates," "believes" or "plans," or comparable terminology, are forward-looking statements based on current expectations and assumptions, and entail various risks and uncertainties that could cause actual results to differ materially from those expressed in such forward-looking statements. Important factors known to Ceridian that could cause such material differences are identified and discussed from time to time in Ceridian's filings with the Securities and Exchange Commission, including matters arising from the SEC investigation, the prior restatements of our financial statements, the pending shareholder litigation, volatility associated with Comdata's fuel price derivative contracts and those factors which are discussed in Ceridian's Annual Report on Form 10-K for the year ended December 31, 2006, which factors are also incorporated herein by reference.

Ceridian undertakes no obligation to correct or update any forward-looking statements, whether as a result of new information, future events or otherwise. You are advised, however, to consult any future disclosure Ceridian makes on related subjects in future reports to the SEC.