This book constitutes the refereed proceedings of the 23rd Conference on Artificial Intelligence, Canadian AI 2010, held in Ottawa, Canada, in May/June 2010. The 22 revised full papers presented together with 26 revised short papers, 12 papers from the graduate student symposium and the abstracts of 3 keynote presentations were carefully reviewed and selected from 90 submissions. The papers are organized in topical sections on text classification; text summarization and IR; reasoning and e-commerce; probabilistic machine learning; neural networks and swarm optimization; machine learning and data mining; natural language processing; text analytics; reasoning and planning; e-commerce; semantic web; machine learning; and data mining.