This book constitutes the refereed proceedings of the third International Joint Conference an Ambient Intelligence, AmI 2012, held in Pisa, Italy, in November 2012. The 18 revised full papers and 5 short papers presented were carefully reviewed and selected from 47 (full papers) respectively 14 (short papers) submissions. From a scientific point of view, the papers make a multidisciplinary approach covering fields like computer science, human computer interaction, electrical engineering, industrial design, behavioral sciences, aimed at enriching physical environments with a network of distributed devices, such as sensors, actuators, and computational resources, in order to support users in their everyday activities.