Ensuring patient safety and providing high-quality health services are the dominant challenges faced by healthcare systems around the world today. The sharing of advanced knowledge and best practice in diagnosis, therapy, process optimization and prevention are essential to achieve this goal; this includes enhanced networking socially and technologically as well as the inclusion of public health and social sciences. This book contains the proceedings of the 13th European Federation for Medical Informatics (EFMI) Special Topic Conference (STC), held in Prague, Czech Republic, in April 2013. The EFMI STC 2013 is Europe’s leading forum for presenting the results of current scientific work in health informatics processes, systems and technologies this year. The title of this 13th conference is Data and Knowledge for Medical Decision Support, and the conference addresses this important field, linking traditional and translational medicine with natural sciences and technology with a view to the design, implementation and deployment of intelligent systems which will meet the expectations of developers and users such as health professionals and patients. Within this context, the authors included here address the important issues of knowledge representation and management, appropriate terminologies and ontologies, the development of reasoning engines, and the modeling and simulation of real systems for decision making. The hot topics of "Big Data" and "Analytics" also receive attention.