&NA;A comprehensive study of nurse practitioners was undertaken by the University of Virginia Schools of Medicine and Nursing in the summer of 1974 to evaluate nurse practitioner training programs of the University of Virginia and to determine the effectiveness and responsibilities of nurse practitioners in various practice settings. Data on nurse practitioners in a number of locations in Virginia and in the Philadelphia metropolitan area were collected and analyzed to determine the way in which the nurse practitioners' time was allocated among various duties and to evaluate nurse practitioner performance by physicians and patients. Nurse practitioners performed a wide variety of clinical and nonclinical tasks. Most physicians were satisfied with the practitioner's performance, although there was some inconsistency between physicians and nurse practitioners regarding actual duties performed. A high percentage of physicians stated they would hire a nurse practitioner to replace one who left their employ. Physicians' reasons for hiring a nurse practitioner, as well as their previous contact with such personnel, were examined. Regarding patient attitudes toward nurse practitioners, data indicated that patients were satisfied with nurse practitioners and felt comfortable being treated by them.