This book constitutes the refereed proceedings of the 7th International Symposium on Component-Based Software Engineering, CBSE 2004, held in Edinburgh, UK in May 2004 as an adjunct event to ICSE 2004. The 12 revised long papers and 13 revised short papers presented together with the abstracts of 2 invited talks were carefully reviewed and selected from 82 submissions. The papers are organized in topical sections on generation and adoptation of component-based systems, tools and building frameworks, components for real-time embedded systems, extra-functional properties of components and component-based systems, and measurement and prediction models for component assemblies.