As more women enter medicine, intriguing questions arise about how physician gender impacts practice style. To measure this influence in primary care encounters, 118 male and 132 female adult new patients, having no stated preference for a specific physician, were randomly assigned to university hospital primary care residents, and their initial encounters were videotaped. Forty-eight male and 33 female physicians participated. Patient health status was assessed before the visit with the Medical Outcomes Study Short-Form General Health Survey. Physician practice style was evaluated by using the Davis Observation Code to analyze videotapes of each initial visit. Patient satisfaction with medical care was assessed with satisfaction questionnaires. Contrary to prior reports, the difference between male and female physicians in total time spent with patients was small and statistically insignificant, and diminished further when controlling for patient gender and health status. Female physicians, however, were observed to engage in more preventive services and to communicate differently with their patients. These differences in practice style appear to explain partially the observed higher patient satisfaction scores for female physicians. This study underscores the importance of careful measurement and control of potential confounding factors in clarifying the impact of physician gender on practice style.