This book constitutes the strictly refereed post-proceedings of the 4th International Workshop on Computational Logic for Multi-Agent Systems, CLIMA IV, held in Fort Lauderdale, Fl, USA in January 2004.  The 11 revised full papers presented together with 2 invited papers were carefully selected during two rounds of reviewing and improvement. The papers are devoted to techniques from computational logic for representing, programming, and reasoning about multi-agent systems. The papers are organized in topical sections on negotiation in MAS, planning in MAS, knowledge revision and update in MAS, and learning in BDI MAS.