This book constitutes the refereed proceedings of the 4th International Conference on Integrated Formal Methods, IFM 2004, held in Canterbury, UK, in April 2004.

The 24 revised full papers presented together with 3 invited papers and one invited tutorial chapter were carefully reviewed and selected from 65 submissions. The papers are devoted to automating program analysis, state/event-based verification, formalizing graphical notions, refinement, object-orientation, hybrid and timed automata, integration frameworks, verifying interactive systems, and testing and assertions.