Data are presented on office-bascd general practitioners and pediatricians working in varying practice settings. Fee-for-service physicians spend more time in direct patient care activities than those in prepaid practice, and devote more time to each patient. The data suggest that the patient load characteristic of general practice in prepaid groups encourages a more assembly line practice which is less responsive to patients than the pattern characteristic of feefor-service practice. Prepaid physicians work during scheduled hours and may deal with increased load by processing patients more rapidly. Fee-for-service physicians tend to respond to increased demand by working longer hours. The responsiveness of primary care physicians to patient problems seems to reflect primarily their social orientations to medical practice and the time pressures they face. Varying practice settings result in different techniques of coping with the pressures of practice. Data are also presented on sociodemographic and professional characteristics of primary care physicians in varying settings, workload, use of diagnostic and laboratory procedures, social orientations to medical practice, satisfactions and dissatisfactions, and attitudes toward sociopolitical aspects of medical care. Suggestions are offered for improving the responsiveness of prepaid practice.