This book constitutes the refereed proceedings of the 10th International Conference on Principles and Practice of Constraint Programming, CP 2004, held in Toronto, Canada, in September 2004. The 46 revised full papers and 16 revised short papers presented together with extended abstracts of 4 invited talks and 31 abstracts of contributions to the doctoral students program were carefully reviewed and selected from 158 submissions. A weather of recent research results on computing with constraints is addressed ranging from foundational and methodological issues to solving real-world problems in various application fields.