This volume contains the proceedings of the 2003 International Conference on Formal Engineering Methods (ICFEM 2003). The conference was the ?fth in a series that began in 1997. ICFEM 2003 was held in Singapore during 5β7 November 2003. ICFEM 2003 aimed to bring together researchers and practitioners from - dustry, academia, and government to advance the state of the art in formal engineering methods and to encourage a wider uptake of formal methods in industry. The Program Committee received 91 submissions from more than 20 co- tries in various regions. After each paper was reviewed by at least three referees in each relevant ?eld, 34 high-quality papers were accepted based on originality, technical content, presentation and relevance to formal methods and software engineering. We wish to sincerely thank all authors who submitted their work for consideration. We would also like to thank the Program Committee members and other reviewers for their great e?orts in the reviewing and selecting process. Weareindebtedtothethreekeynotespeakers,Prof.IanHayesoftheUniv- sity of Queensland, Prof. Mathai Joseph of the Tata Research, Development and DesignCentre,andDr.ColinOβHalloranofQinetiQ,foracceptingourinvitation to address the conference.