This report summarizes the outcome of the 5th Workshop on AspectOriented Modeling (AOM) held in conjunction with the 7th International Conference on the Unified Modeling Language – UML 2004 – in Lisbon, Portugal. The workshop brought together researchers and practitioners from two communities: aspect-oriented software development (AOSD) and software model engineering. It provided a forum for discussing the state of the art in modeling crosscutting concerns at different stages of the software development process: requirements elicitation and analysis, software architecture, detailed design, and mapping to aspect-oriented programming constructs. This paper gives an overview of the accepted submissions, and summarizes the results of the different discussion groups.