Pediatric providers can expect that 1 of every 10 patients they see will have a chronic, activity-limiting health condition. Thanks to earlier diagnosis and improved therapies, most of these children will live well into adulthood. This means that eventually they will require care that focuses on adult health issues. Providers in the United States and around the world are recognizing the need for coordinated processes to transition adolescents and young adults with chronic conditions to adult health care. These models rely on the participation and input of the adolescent, his or her family, and pediatric and adult health professionals. This paper distinguishes medical transition from medical transfer; discusses potential barriers to transition; examines new initiatives to develop and study transition models; and reviews federal legislation influencing health care transitions.