The following technical report is available from http://aib.informatik.rwth-aachen.de/: Slim Abdennadher, Christophe Ringeissen (eds.) RULE 04 -- Fifth International Workshop on Rule-Based Programming 2004-04 This report contains the proceedings of the 5th International Workshop on Rule-Based Programming (RULE 2004), which was held on June 1, 2004 as part of the Federated Conference on Rewriting, Deduction, and Programming (RDP 2004) in Aachen, Germany.