Advances in sensor technology, processing speed, high-speed networking, and the massive digital storages are being incorporated into today's healthcare practice. Tremendous amounts of medical multimedia data are captured and recorded in digital format during the daily clinical practice, medical research, and education. Intelligent medical knowledge discovery and retrieval from medical multimedia data is very useful and highly desirable. Motivated by the huge potential benefits, we have organized the ACM International Workshop on Medical Multimedia Analysis and Retrieval (MMAR2011), held in conjunction with The Annual ACM International Conference on Multimedia (ACM Multimedia 2011). In this paper, we first introduce the background and overview of the workshop. Then we introduce the workshop review process, followed with a brief introduction of the accepted papers in this workshop, as well as the conclusion.