This paper presents an outline of the scope for the application of decision theory to health care. Firstly, the main approaches to and assumptions of decision theory are discussed. Secondly, health care decision making is reviewed. It is noted that decision theory can be applied to either the health care professional or to the lay person. Applications of decision theory to clinical practice, to the management of care and to resourcing are considered. Thirdly, some areas which would repay further research are identified. These include social processes in individual and group decision making, the temporal distribution of outcomes and the development of techniques capable of dealing with the complex and dynamic features of decisions. On the basis of the foregoing, some conclusions are drawn.