This book constitutes the refereed proceedings of the 5th International Conference on Product Focused Software Process Improvement, PROFES 2004, held in Kansai Science City, Japan in April 2004. The 41 revised full papers presented were carefully reviewed and selected and constitute a balanced mix of academic and industrial aspects. The papers are organized in topical sections on software process improvement, software quality, measurement, methods and tools, experimental software engineering, industrial experiences, agile methods, software process assessment, requirements engineering, and software reuse and COTS.