Nested within a 40-year trend of specialty-to-population growth outpacing that of primary care is variability in the rate of expansion within the different primary care disciplines.1 With continued population aging trends, low annual birth rate, and expected health insurance expansion, it is vital that physician workforce policy be aimed at meeting population needs to deliver optimal primary care. Family medicine, general internal medicine, and general pediatrics comprise the majority of the primary care physician workforce in the United States. To better understand trends in the primary care physician workforce, we have examined the growth of family physicians, general pediatricians, and general internists providing direct patient care.