The book "Knowledge Representation for Health-Care: Data, Processes and Guidelines" is the result of the merging of two series of workshops focused on computerized guidelines and protocols as well as knowledge management for health procedures. This fusion led to the KR4HC workshop, which took place during the 12th Conference on Artificial Intelligence in Medicine (AIME 2009) in Verona, Italy. In addition to the complete workshop papers, the book includes invited, peer-reviewed articles that present valuable insights from these fields. The KR4HC workshop continues the tradition of successful guidelines workshops that have been held regularly since 2000. The aim is to explore innovative approaches to modeling and developing guidelines and to promote collaboration between different research areas of artificial intelligence.