This paper reports on the results of the Fifth International Workshop on Object-Oriented Reengineering in Oslo on June 15, 2004. It enumerates the presentations made, classifies the contributions and lists the main results of the discussions held at the workshop. As such it provides the context for future workshops around this topic. 1 Objectives of the Workshop The workshop on Object-Oriented Reengineering was co-located with the 18th European Conference on Object-Oriented Programming, and took place at Oslo (Norway) on June 15, 2004. There were 13 participants, most of which contributed with a position paper that was reviewed and revised before the workshop. The workshop gathered people working on solutions to reengineer objectoriented legacy systems, a vital matter in today’s software industry. We claim that software evolution and reengineering is a key issue of software engineering, be it object-oriented or not. This shift of importance is starting to be noticed in research and ...