This volume contains papers presented at WLPE 2005, 15th International Workshop on Logic-based methods in Programming Environments. The aim of the workshop is to provide an informal meeting for the researchers working on logic-based tools for development and analysis of programs. This year we emphasized two aspects: on one hand the presentation, pragmatics and experiences of tools for logic programming environments; on the other one, logic-based environmental tools for programming in general. The workshop took place in Sitges (Barcelona), Spain as a satellite workshop of the 21th International Conference on Logic Programming (ICLP 2005). This workshop continues the series of successful international workshops on logic programming environments held in Ohio, USA (1989), Eilat, Israel (1990), Paris, France (1991), Washington, USA (1992), Vancouver, Canada (1993), Santa Margherita Ligure, Italy (1994), Portland, USA (1995), Leuven, Belgium and Port Jefferson, USA (1997), Las Cruces, USA (1999), Paphos, Cyprus (2001), Copenhagen, Denmark (2002), Mumbai, India (2003) and Saint Malo, France (2004). We have received eight submissions (2 from France, 2 Spain-US cooperations, one Spain-Argentina cooperation, one from Japan, one from the United Kingdom and one Sweden-France cooperation). Program committee has decided to accept seven papers. This volume contains revised versions of the accepted papers. We are grateful to the authors of the papers, the reviewers and the members of the Program Committee for the help and fruitful discussions.