This two-volume set LNAI 6437 and 6438 constitutes the refereed proceedings of the 9th Mexican International Conference on Artificial Intelligence, MICAI 2010, held in Pachuca, Mexico, in November 2010. Based on rigorous peer reviews, the program committee carefully selected 82 revised papers from 301 submissions for presentation in two volumes. The second volume includes 44 papers focusing on soft computing. The papers are organized in topical sections on machine learning and pattern recognition; automatic learning for natural language processing; evolutionary algorithms and other naturally-inspired algorithms; hybrid intelligent systems and neural networks; and fuzzy logic.