These are the proceedings of CHES 2001, the third Workshop on Cryptographic Hardware and Embedded Systems. The ?rst two CHES Workshops were held in Massachusetts, and this was the ?rst Workshop to be held in Europe. There was a large number of submissions this year, and in response the technical program was extended to 2 1/2 days. As is evident by the papers in these proceedings, many excellent submissions were made. Selecting the papers for this years CHES was not an easy task, and weregretthatwehadtorejectseveralveryinterstingpapersduetotheac l kof time. There were 66 submitted contributions this year, of which 31, or 47%, were selected for presentation. If we look at the number of submitted papers at CHES 99 (42 papers) and CHES 2001 (51 papers), we observe a steady increase. We interpret this as a continuing need for a workshop series which combines theory and practice for integrating strong security features into modern communications and computer applications. In addition to the submitted contributions, Ross Anderson from Cambridge University, UK, and Adi Shamir from The Weizmann Institute, Israel, gave invited talks. As in previous years, the focus of the workshop is on all aspects of cryp- graphichardwareandembeddedsystemdesign.Ofspecialtwerecont- butions that describe new methods for e?cient hardware implementations and high-speed software for embedded systems, e.g., smart cards, microprocessors, DSPs, etc. CHES also continues to be an important forum for new theoretical andpractical?ndingsintheimportantandgrowing?eldofside-channelattacks.