U.S. health care is changing, and it will continue to change across multiple dimensions: a different mix of patients; more ambulatory, chronic care and less acute, inpatient care; an older population; expanded insurance coverage; a team approach to care; rapid growth of subspecialty care; growing emphasis on cost-effective care; and rapid technological change. These changes demand a corresponding evolution in physician roles and training. However, despite innovation in content and teaching methods, there has been little alteration to the basic structure of medical education since the Flexner Report sparked widespread reform in 1910. Looking to the future, medical education might evolve to include preparation for a team approach to care via practical training for multispecialty collaborative practice and preparing physicians to be leaders of primary care teams that include nonphysician providers; shorter training for some physicians via flexible pathways and "fast tracks" at each phase of training; cost-effective care in clinical practice; increased training in geriatrics; and "on ramps" and "off ramps" along the physician career path for flexible training over a lifetime. Although the challenges facing the health care system are great, meeting changing health care needs must begin at the foundation, in medical education.