This book includes the proceedings of the 12th RoboCup International Symposium, held in Suzhou, China, on July 15-18, 2008 in conjunction with Soccer, Rescue, @Home and Junior competitions and demonstrations. Papers presented at the symposium focused on diverse areas related to the main RoboCup threads and to Artificial Intelligence and Robotics in general. The 36 revised full papers and 20 revised poster papers presented were carefully reviewed and selected from 91 submissions. The contributions provide a valuable source of references and inspiration for R and D professionals interested in robotics and artificial intelligence.