This report describes the development and initial validation of a self-report instrument designed to measure beliefs about psychosocial aspects of patient care held by primary care physicians. The strategy used was borrowed from psychological measurement: a rational scale was constructed based on an existing theoretical framework concerning the physician's role, what the patient wants and physicians' reactions to their patients as people. The validation step compared scale scores obtained by diverse groups of providers. Psychometric characteristics of the Physician Belief Scale are adequate: scores follow an approximately normal distribution with the mean near the midpoint of possible scores. Lower scores on the Scale represent a more psychosocial approach to patient care. Initial construct validation was successful: physicians from four disciplines obtained scores congruent with expectations about the psychosocial orientations of the disciplines. A reliable and valid measure has been developed to assess physicians' psychosocial beliefs. The instrument may be used to evaluate effectiveness of behavioral science teaching, describing regional or other differences in physician beliefs within and between specialties and estimating changes in provider beliefs.