ADECCO IS ADDED TO THE DOW JONES SUSTAINABILITY INDEXES WORLD AND EUROPE

Press Release

Adecco is added to the Dow Jones Sustainability Indexes World and Europe

Zurich, Switzerland, September 19, 2011: Adecco Group, the global leader in Human Resource services, today announces its inclusion in the Dow Jones Sustainability World and Europe Indexes (DJSI). The DJSI, in cooperation withSustainable Asset Management (SAM), recognise the Adecco Group as one of the sustainability leaders in the Industrial Goods and Services sector.

Adecco was compared to almost 1,500 of the largest companies worldwide. The assessment consists of an in-depth analysis of the companies’ performance across economic, environmental and social criteria such as corporate governance, environmental risks and stakeholder relations.

Launched in 1999, the DJSI in cooperation with SAM follow a best-in-class approach to measuring sustainable corporate performance across the world’s 2,500 largest companies and 57 business sectors.  SAM’s comprehensive Corporate Sustainability Assessment has a strong focus on long-term shareholder value.

For further information please contact:

Adecco Corporate Investor Relations

Investor.relations@adecco.com or +41 (0) 44 878 89 89

Adecco Corporate Press Office

Press.office@adecco.com or +41 (0) 44 878 87 87

Forward-looking statements

Information in this release may involve guidance, expectations, beliefs, plans, intentions or strategies regarding the future. These forward-looking statements involve risks and uncertainties. All forward-looking statements included in this release are based on information available to Adecco S.A. as of the date of this release, and we assume no duty to update any such forward-looking statements. The forward-looking statements in this release are not guarantees of future performance and actual results could differ materially from our current expectations. Numerous factors could cause or contribute to such differences. Factors that could affect the Company’s forward-looking statements include, among other things: global GDP trends and the demand for temporary work; changes in regulation of temporary work; intense competition in the markets in which the Company operates; integration of acquired companies; changes in the Company’s ability to attract and retain qualified internal and external personnel or clients; the potential impact of disruptions related to IT; any adverse developments in existing commercial relationships, disputes or legal and tax proceedings.

About the Adecco Group

The Adecco Group, based in Zurich, Switzerland, is the world’s leading provider of HR solutions. With approximately 33,000 FTE employees and over 5,500 branches, in over 60 countries and territories around the world, Adecco Group offers a wide variety of services, connecting over 750,000 associates with well over 100,000 clients every day. The services offered fall into the broad categories of temporary staffing, permanent placement, outsourcing, consulting and outplacement. The Adecco Group is a Fortune Global 500 company.

Adecco S.A. is registered in Switzerland (ISIN: CH0012138605) and listed on the SIX Swiss Exchange (ADEN).