This book constitutes the refereed proceedings of the 16th Conference of the Canadian Society for Computational Studies of Intelligence, AI 2003, held in Halifax, Canada in June2003. The 30 revised full papers and 24 revised short papers presented were carefully reviewed and selected from 106 submissions. The papers are organized in topical sections on knowledge representation, search, constraint satisfaction, machine learning and data mining, AI and Web applications, reasoning under uncertainty, agents and multi-agent systems, AI and bioinformatics, and AI and e-commerce.