This book constitutes the refereed proceedings of the 12th Brazilian Symposium on Artificial Intelligence, SBIA '95, held in Campinas, Brazil, in October 1995. The book presents three invited papers and 31 revised full papers selected from a total 57 submissions, more than half of them coming from abroad. The papers are organized in sections on knowledge representation and automated reasoning, tutoring systems, machine learning, neural networks, distributed artificial intelligence, knowledge acquisition and knowledge bases, and natural language processing.