This Book Constitutes The Refereed Proceedings Of The Third Miccai Workshop On Medical Content-based Retrieval For Clinical Decision Support, Mcbr-cbs 2012, Held In Nice, France, In October 2012. The 10 Revised Full Papers Presented Together With 2 Invited Talks Were Carefully Reviewed And Selected From 15 Submissions. The Papers Are Divided On Several Topics On Image Analysis Of Visual Or Multimodal Medical Data (x-ray, Mri, Ct, Echo Videos, Time Series Data), Machine Learning Of Disease Correlations In Visual Or Multimodal Data, Algorithms For Indexing And Retrieval Of Data From Visual Or Multimodal Medical Databases, Disease Model-building And Clinical Decision Support Systems Based On Visual Or Multimodal Analysis, Algorithms For Medical Image Retrieval Or Classification, Systems Of Retrieval Or Classification Using The Imageclef Collection.