Communication patterns between physicians and their assistants (Medex) were observed in 19 practices to describe and evaluate the nature of their relationship. Observations demonstrated that interaction around patient problems was approximately 30 minutes per day and informal, with the Medex more often initiating the contact. Medex were more likely to ask for, and physicians were more likely to give, suggestions. Physicians appeared to regard the accomplishment of the immediate task as more important than maintaining good relations. In most practices, supervision was available when requested. Generally, both the physician and the Medex show a striking similarity in communication styles.