The debate on the efficiency of the health care system in Italy requires a developing dialogue between clinicians, epidemiologists and health economists. In this perspective the meaning of economic efficiency and its relationship with effectiveness are presented, either at production unit level either at system level. Application of criteria of efficiency is not independent from value judgements. The conflict between clinical freedom and controls on health care expenditure have ever been and it may not be eliminated, but compounded by expliciting the criteria of choice and by defining the responsibilities of health policy makers and clinicians. An example is represented by the recent Oregon's experiment. In the agenda of the future change of the Italian National Health Service, mechanisms of cost-effectiveness resource allocation criteria are suggested to be included.