Hospital medicine in the United States is the medical specialty concerned with the care of acutely ill hospitalized patients. Physicians whose primary professional focus is caring for hospitalized patients only while they are in the hospital are called hospitalists. This type of medical practice has extended beyond the United States into Australia and Canada. Most physicians who refer to themselves as hospitalists focus their practice upon hospitalized patients but do not necessarily have board certification in hospital medicine. The term hospitalist was first coined by Robert Wachter and Lee Goldman in a 1996 New England Journal of Medicine article. The scope of hospital medicine includes acute patient care, teaching, research, and executive leadership related to the delivery of hospital-based care. Hospital medicine, like emergency medicine, is a specialty organized around a site of care (the hospital), rather than an organ (like cardiology), a disease (like oncology), or a patient’s age (like paediatrics). The emergence of hospital medicine has both similarities with and differences from acute medicine in the United Kingdom, reflecting health system differences.