A large, widening gap exists between the incomes of primary care physicians and those of many specialists. This disparity is important because noncompetitive primary care incomes discourage medical school graduates from choosing primary care careers. The Resource-Based Relative Value Scale, designed to reduce the inequality between fees for office visits and payment for procedures, failed to prevent the widening primary care-specialty income gap for 4 reasons: 1) The volume of diagnostic and imaging procedures has increased far more rapidly than the volume of office visits, which benefits specialists who perform those procedures; 2) the process of updating fees every 5 years is heavily influenced by the Relative Value Scale Update Committee, which is composed mainly of specialists; 3) Medicare's formula for controlling physician payments penalizes primary care physicians; and 4) private insurers tend to pay for procedures, but not for office visits, at higher levels than those paid by Medicare. Payment reform is essential to guarantee a healthy primary care base to the U.S. health care system.