This book constitutes the refereed proceedings of the 14th International Symposium Fundamentals of Computation Theory, FCT 2003, held in Malmo, Sweden in August 2003.The 36 revised full papers presented together with an invited paper and the abstracts of 2 invited talks were carefully reviewed and selected from 73 submissions. The papers are organized in topical sections on approximibility, algorithms, networks and complexity, computational biology, computational geometry, computational models and complexity, structural complexity, formal languages, and logic.