This book constitutes the refereed proceedings of the 6th International Symposium on Self-Stabilizing Systems, SSS 2003, held in San Francisco, CA, USA, in June 2003.The 15 revised full papers presented were carefully reviewed and selected from 27 submissions. The papers address self-stabilization issues for various types of systems and software including communication protocols, sensor networks, biological systems, and directed networks; several new algorithms are presented.