This volume contains the papers presentedat the 20th InternationalConference onLogicProgramming, held in Saint-Malo, France, September 6 10,2004.Since the ?rst meeting in this series, held in Marseilles in 1982, ICLP has been the premier international conference for presenting research in logic programming. This year, we received 70 technical papers from countries all over the world, and the ProgramCommittee accepted 28 of them for presentation;they are included in this volume. A stand-by-your-postersession took place during the conference. It servedas...