This book constitutes the refereed proceedings of the Third International Conference on E-Commerce and Web Technologies, EC-Web 2002, held in Aix-en-Provence, France, in September 2002. The 40 revised full papers presented together with two invited contributions were carefully reviewed and selected from more than 100 submissions. The papers are organized in topical sections on auction and negotiation technology, applications, architecture, agents, web query processing, web data integration, security and privacy, recommender systems, emerging standards, business models, and e-payment.