These are the refereed proceedings of the 13th International Conference on Concurrency Theory, CONCUR 2002, held in Brno, Czech Republic in August 2002. The 32 revised full papers presented together with abstracts of seven invited contributions were reviewed and selected from 101 submissions. The papers are organized in topical sections on verification and model checking, logic, mobility, probabilistic systems, models of computation and process algebra, security, Petri nets, and bisimulation.