What economists can learn from sociologists with regard to the economic theory of agency in health care is considered. Whilst the concept of agency has become widely accepted in health economics, its application to the doctor-patient relationship remains somewhat limited. Research is needed on the nature of the patient's and doctor's utility functions before an efficient outcome in health care can be achieved. Economists have much to learn from sociologists concerning the nature of patient's and doctor's utility functions. Only when economists take account of this literature will moves towards an efficient outcome in health care be achieved.