This study examines the influence of physician networks on the utilization of computers in clinical practice. Data on patient referrals, consultations, professional discussions, and on-call coverage were collected from 24 physicians who comprise a private group practice. Their utilization of a computerized hospital medical information system (HIS) in caring for patients admitted to a 1160-bed private, university affiliated, teaching hospital was determined. A matrix representing the professional relations among these physicians was subjected to smallest space analysis, a form of multidimensional scaling. Also, a number of indices that describe structural and interactional properties of the network and individual physicians were computed. The three-dimensional representation of the network that resulted from the analysis suggests a two-step process of adoption and utilization of medical technology. Physicians who were engaged in outside professional activities and in the training of medical students and house staff were more likely to utilize the system in caring for patients. These physicians, who were more centrally located and dominant in the referral and consultation process, were more likely to influence the practice patterns of their colleagues. The use of network analysis to identify influential physicians whose involvement is essential to the success of efforts aimed at introducing computers into clinical practice is discussed.