This book constitutes the refereed proceedings of the International Workshop on Augemented Environments for Computer-Assisted Interventions, held in conjunction with MICCAI 2012, in Nice, France in September 2012. The 16 revised full papers presented were carefully reviewed and selected from 22 submissions. The papers cover the topics of image registration and fusion, calibration, visualization and 3D perception, hardware and optical design, real-time implementation, as well as validation, clinical applications, and clinical evaluation.