This book constitutes the refereed proceedings of the 6th International Symposium on Formal Techniques in Real-Time and Fault-Tolerant Systems, FTRTFT 2000, held in Pune, India in September 2000. The 21 revised full papers presented together with three invited contributions were carefully reviewed and selected from numerous submissions. The papers are organized in topical sections on model checking, fault tolerance, scheduling, validation, verification, logic and automata.