This book constitutes the refereed proceedings of the 12th Conference of the Spanish Association for Artificial Intelligence, CAEPIA 2007, held in Salamanca, Spain, in November 2007, in conjunction with the 7th Workshop on Artificial Intelligence Technology Transfer, TTIA 2007. The 28 revised full papers presented were carefully selected during two rounds of reviewing and improvement from 134 submissions. The papers address all current issues of artificial intelligence ranging from methodological and foundational aspects to advanced applications in various fields.