We analyzed data from the National Ambulatory Medical Care Survey to compare the style of practice of two primary-care providers, general internists and family-general practitioners. Whereas internists spent 18.4 minutes with the average patient, family-general practitioners spent 13.0 minutes. Whereas internists used laboratory tests in 73 per cent of visits and x-ray tests in 53 per cent, family-general practitioners used these studies in 34 and 19 per cent of visits. Internists provided instructions regarding health problems in 17.8 per cent of visits, and family-general practitioners in 12.4 per cent. The two provider groups did not differ in terms of therapy for emotional problems, both providing it in a relatively low proportion of visits (3 per cent). Whether by choice or necessity, family-general practitioners spent less time examining and instructing patients, and they ordered fewer laboratory and x-ray studies. The implications of these differences for the cost and quality of primary care need further study.