Analysis of national survey data on physician-patient encounters raises questions about physician education and manpower policy. Data compiled by the University of Southern California Medical Activities and Manpower Projects and the United States Bureau of Health Professionals reveal differences among internists, cardiologists, family practitioners, and pediatricians in procedures used for diagnosing and treating several frequently encountered conditions. Differences are observed in expenditure of time and use of a broad range of diagnostic and therapeutic techniques. These differences remain significant even after several important characteristics of individual physicians, patients, and the practice environment have been controlled. Findings from this study underscore the necessity of reviewing the content of medical education and policies that encourage a broad range of specialists to provide primary care. The findings also emphasize the need to address the physician's knowledge base in promoting changes in practice patterns.