Pediatric hospital medicine (PHM), as it is known now, has arrived. It is no longer merely a movement, nor is it only a reaction to residency work-hour restrictions or a call for heightened attention to safety for increasingly acute and complex hospitalized children. It is a well-defined field of pediatrics, dedicated to improving the care of hospitalized children, both at the point of care and through systemwide transformations. It requires a specialized knowledge base and skill set to practice with efficiency and expertise. It is the professional choice for approximately 2500 practicing pediatricians in the United States (C. Collier, Society of Hospital Medicine, written and oral communication, February 2012; and N. Alexander, American Academy of Pediatrics, written and oral communication, October 2012), an active and forward-thinking community supported by 3 partner organizations (the American Academy of Pediatrics, Academic Pediatric Association, and Society of Hospital Medicine) and guided by the Joint Council of Pediatric Hospital Medicine, a coordinating body among these organizations.