Rapid technical advances in medical imaging, including its growing application to drug/gene therapy and invasive/interventional procedures, have attracted significant interest in close integration of research in life sciences, medicine, physical sciences and engineering. This is motivated by the clinical and basic science research requi- ment of obtaining more detailed physiological and pathological information about the body for establishing localized genesis and progression of diseases. Current research is also motivated by the fact that medical imaging is increasingly moving from a primarily diagnostic modality towards a therapeutic and interventional aid, driven by recent advances in minimal-access and robotic-assisted surgery. It was our great pleasure to welcome the attendees to MIAR 2004, the 2nd Int- national Workshop on Medical Imaging and Augmented Reality, held at the Xia- shan (Fragrant Hills) Hotel, Beijing, during August 19–20, 2004. The goal of MIAR 2004 was to bring together researchers in computer vision, graphics, robotics, and medical imaging to present the state-of-the-art developments in this ever-growing research area. The meeting consisted of a single track of oral/poster presentations, with each session led by an invited lecture from our distinguished international f- ulty members. For MIAR 2004, we received 93 full submissions, which were sub- quently reviewed by up to 5 reviewers, resulting in the acceptance of the 41 full - pers included in this volume.