This book constitutes the refereed proceedings of the 10th International Workshop on Quality of Service, IWQoS 2003, held in Berkeley, CA, USA, in June 2003. The 27 revised full papers presented were carefully reviewed and selected from numerous submissions. The papers are organized in topical sections on analysis and modeling, resource allocation and admission control, multimedia and incentives, dependability and fault tolerance, routing, availability and dependability, Web services, rate-based QoS, and storage.