To document the volume and kinds of ambulatory care, particularly primary care, being provided in a medically self-contained community, a survey was conducted in a county in a Middle Atlantic State during the summer of 1974 at all sites where physicians provided ambulatory care. These sites included not only physicians' offices, but also the emergency room, public health clinics, and physician-patient telephone encounters. Primary care was found to constitute 77 percent of all ambulatory care in the county and to account for 96 percent of all visits to primary care physicians. It also accounted for more than 50 percent of the visits to all physicians except the surgical subspecialists. Most of the primary care visits were for common disorders, common procedures, and common preventive measures. Distinct patterns were observed in the primary care morbidity treated by primary care physicians and that treated by specialists--patterns that seemed appropriate for those practices. The specialties of the physicians who were available to the population may have influenced morbidity patterns in the community surveyed. The primary care provided by primary care specialists appeared to differ in some functional aspects from that provided by other specialists.