This book constitutes the refereed proceedings of the 5th International Conference on Formal Engineering Methods, ICFEM 2003, held in Singapore in November 2003.

The 34 revised full papers presented together with 3 invited contributions were carefully reviewed and selected from 91 submissions. The papers are organized in topical sections on testing and validation, state diagrams, PVS/HOL, refinement, hybrid systems, Z/Object-Z, Petri nets, timed automata, system modeling and checking, and semantics and synthesis.