This chapter uses “knowledge mobilization” as an umbrella term to cover activities aimed at collating and communicating research-based knowledge within the health care system and within health care organizations. It explores the nature, use and flow of knowledge, focusing in particular on the role of research-based knowledge and its interactions with other forms of knowing, and on the organizational and management arrangements for health care delivery rather than on evidence-based practice per se. The chapter is underpinned by the premise that knowledge flow in health care is often slow, intermittent and uncertain. Specific, active, knowledge mobilization strategies that take account of context, politics and the individuals and groups involved are therefore needed to help ensure that research-based knowledge informs policy and practice.