This book constitutes the refereed proceedings of the 12th International Workshop on Cooperative Information Agents, CIA 2008, held in Prague, Czech Republik, in September 2008. The book contains 5 invited papers and 19 revised full papers which were carefully reviewed and selected from 38 submissions. The papers are organized in topical sections on Trust, Applications, Coordination and Communications, and Negotiation.

The aim of the CEEMAS conference series is to provide a biennial forum for the presentation of multi-agent research and development results. With its p- ticular geographicalorientation towards Central and Eastern Europe, CEEMAS has become an internationally recognised event with participants from all over the world. After the successful CEEMAS conferences in St. Petersburg (1999), Cracow (2001) and Prague (2003), the 2005 CEEMAS conference takes place in Budapest. The programme committee of the conference series consists of est- lished researchers from the region and renowned international...