This book constitutes the thoroughly refereed post-workshop proceedings of the 6th International Workshop on Agents and Peer-to-Peer Computing, AP2PC 2007, held in Honululu, Hawaii, USA, in May 2007, in the context of the 6th International Joint Conference on Autonomous Agents and Multi-Agent Systems, AAMAS 2007. The 8 revised full papers presented together with 1 summary paper were carefully reviewed and selected from 14 initial submissions; they are fully revised to incorporate reviewers' comments and discussions at the workshop. The volume is organized in topical sections on agent and peer trust, performance and testing, grid and distributed computing, as well as location and search services.