This book constitutes the thoroughly refereed post-proceedings of the First International Workshop on Databases, Information Systems, and Peer-to-Peer Computing, DBISP2P 2003, held in Berlin, Germany in September 2003 as a satellite event of VLDB 2003.The 16 revised full papers presented together with the abstract of an invited contribution were carefully selected during two rounds of reviewing and improvement. The papers are organized in topical sections on structure in P2P networks, semantics and data integration, data streams and publish/subscribe, and data structures and query processing.