Although humanism has emerged as an important issue in medical education and practice, there is no standardized definition of humanism or an instrument that measures patients' perceptions of their physician's level of humanism. This study addressed these three issues: 1) A definition of physician humanism was developed based on the current literature; 2) an instrument was designed that measured patients' perceptions of humanism in their family physicians; and 3) health outcome variables were measured relative to these perceptions. The design was a cross-sectional survey of 185 randomly selected patients from two family practice sites. The questionnaire consisted of a humanism scale, in addition to items to assess patient satisfaction and patients' adherence to medical advice regarding exercise, diet, and smoking cessation. A positive association was found between perceived physician humanism and patient satisfaction. Greater success in patients' attempts to quit smoking was associated with higher physician humanism. The implications of these findings for evaluation and training of health care providers and patients' use of health care services are discussed.