The 18 revised full papers presented here were selected from a total of 68 submissions from the 17th Conference on the Foundations of Software Technology and Theoretical Computer Science. Also included are five invited papers by Ed Clarke, Deepak Kapur, Madhu Sudan, Vijaya Ramachandran and Moshe Vardi. Among the topics addressed are concurrency, Petri nets, graph computations, program verification, model checking, recursion theory, rewriting and error-correcting codes.