The refereed proceedings of the 7th European Conference on Symbolic and Quantitative Approaches to Reasoning with Uncertainty, ECSQARU 2003, held in Aalborg, Denmark in July 2003. The 47 revised full papers presented together with 2 invited survey articles were carefully reviewed and selected for inclusion in the book. The papers are organized in topical sections on foundations of uncertainty concepts, Bayesian networks, algorithms for uncertainty inference, learning, decision graphs, belief functions, fuzzy sets, possibility theory, default reasoning, belief revision and inconsistency handling, logics, and tools.