This book constitutes the refereed proceedings of the 15th Conference of the Spanish Association for Artificial Intelligence, CAEPIA 20013, held in Madrid, Spain, in September 2013. The 27 revised full papers presented were carefully selected from 66 submissions. The papers are organized in topical sections on Constraints, search and planning, intelligent Web and information retrieval, fuzzy systems, knowledge representation, reasoning and logic, machine learning, multiagent systems, multidisciplinary topics and applications, metaheuristics, uncertainty in artificial intelligence.