Adecco Group AG

Prospectus • Jun 2, 2011

Supplementary Prospectus dated 2 June 2011

ADECCO S.A.

(incorporated with limited liability in Switzerland)

ADECCO FINANCIAL SERVICES (BERMUDA) LTD.

(incorporated with limited liability in Bermuda)

ADECCO INTERNATIONAL FINANCIAL SERVICES B.V.

(incorporated with limited liability in The Netherlands)

EUR 2,000,000,000 Euro Medium Term Note Programme unconditionally and irrevocably guaranteed by

ADECCO S.A.

(incorporated with limited liability in Switzerland)

This Supplementary Prospectus (the Supplement) to the Base Prospectus dated 25 March 2011 (the Prospectus) constitutes a supplementary prospectus for the purposes of Section 87G of the Financial Services and Markets Act 2000 (the FSMA) and is prepared in connection with the EUR 2,000,000,000 Euro Medium Term Note Programme (the Programme) established by Adecco S.A. (in its capacity as an Issuer, Adecco), Adecco Financial Services (Bermuda) Ltd. (AFS) and Adecco International Financial Services B.V. (AIFS) and unconditionally and irrevocably guaranteed by Adecco S.A. (in its capacity as Guarantor, the Guarantor). Terms defined in the Prospectus have the same meaning when used in this Supplement.

The purpose of this Supplement is to incorporate by reference in the Prospectus the auditors' report and audited non-consolidated annual financial statements of AIFS for the financial year ended 31 December 2010 and to update and amend the "Significant or Material Change" paragraph relating to AIFS contained in paragraph (c) of the section entitled "General Information" in the Prospectus.

This Supplement and the Prospectus (together, the Adecco Prospectus) comprise a base prospectus for the purposes of Article 5.4 of Directive 2003/71/ EC (the Prospectus Directive). Adecco (in its capacity as an Issuer and Guarantor) accepts responsibility for the information contained in the Adecco Prospectus. The information contained in the Adecco Prospectus is, to the best of the knowledge of Adecco (having taken all reasonable care to ensure that such is the case), in accordance with the facts and does not omit anything likely to affect the import of such information.

With the exception of (i) the information contained in the sections entitled "Description of Adecco S.A." on pages 61 to 75 of the Prospectus and ''Description of Adecco Financial Services (Bermuda) Ltd.'' on page 76 of the Prospectus, (ii) the information contained in the documents referred to in paragraphs (a), (b), (e) and (f) of the section entitled ''Documents Incorporated by Reference'' on page 15 of the Prospectus and (iii) the information contained in paragraphs (a) and (c) under the heading "Authorisation" on page 87 of the Prospectus, (a) and (b) under the heading "Significant or Material Change" on page 88 of the Prospectus and (a) and (b) under the heading "Litigation" on page 88 of the Prospectus, in each case of the section entitled ''General Information'', this Supplement and the Prospectus (together, the AIFS Prospectus) comprise a base prospectus for the purposes of the Prospectus Directive. AIFS accepts responsibility for the information contained in the AIFS Prospectus. The information contained in the AIFS Prospectus is, to the best of the knowledge of AIFS (having taken all reasonable care to ensure that such is the case), in accordance with the facts and does not omit anything likely to affect the import of such information.

This Supplement and the documents incorporated by reference in this Supplement can be viewed on the website of the Regulatory News Service operated by the London Stock Exchange at http://www.londonstockexchange.com/exchange/prices-and-news/news/market-news/market-newshome.html.

This Supplement is supplemental to, and should be read in conjunction with, the Prospectus and all documents which are incorporated herein or therein by reference. To the extent that there is any inconsistency between (a) any statement in this Supplement or any statement incorporated by reference into the Prospectus by this Supplement and (b) any other statement in, or incorporated by reference in, the Prospectus, the statements in (a) above will prevail.

Any documents themselves incorporated by reference in the documents incorporated by reference in this Supplement shall not form part of this Supplement.

Save as disclosed in this Supplement, no other significant new factor, material mistake or inaccuracy relating to information included in the Prospectus has arisen or been noted, as the case may be, since the publication of the Prospectus.

An investor should be aware of its rights arising pursuant to Section 87Q(4) of the FSMA.

Audited non-consolidated annual financial statements of AIFS for the financial year ended 31 December 2010

The auditors' report and audited non-consolidated annual financial statements of AIFS for the financial year ended 31 December 2010, which have previously been published or are published simultaneously with this Supplement and have been filed with the Financial Services Authority, shall, by virtue of this Supplement, be incorporated in, and form part of, the Prospectus.

Significant or Material Change

The information contained in paragraph (c) of the section entitled "General Information - Significant or Material Change" on page 88 of the Prospectus shall be deleted and replaced with the following wording:

"(c) There has been no significant change in the financial or trading position of AIFS since 31 December 2010 and no material adverse change in the prospects of AIFS since 31 December 2010."