Little is known about physicians' exposure to managed care techniques that affect clinical practice. In 1995, we conducted a survey of 2,003 U.S. physicians asking them about their share of patients subject to a variety of managed care techniques. Nationally, 24% of physicians received some form of capitation payment for their patients. The two most widely used techniques were utilization review (UR), applied to an average of 59% of patients, and discounted fees, applied to an average of 38% of patients. Although UR was common, ultimate denial rates of coverage were very low: at most 3% for the types of care studied. Use of managed care techniques varied more within states than between states. Conventional measures of HMO market penetration revealed little about how managed care affects physicians.