This book constitutes the refereed proceedings of the 9th International Conference on Formal Engineering Methods, ICFEM 2007, held in Boca Raton, Florida, USA, November 14-15, 2007. The 19 revised full papers together with two invited talks presented were carefully reviewed and selected from 38 submissions. The papers address all current issues in formal methods and their applications in software engineering. The papers are organized in topical sections.