This paper porports to explicate the factors determining the scope of public health in advanced capitalist countries. A few studies have veen conducted for such a purpose, yet even these studies show the deficiency of failing to consider a very important factor : the influence of medical profession. Since medical profession has played a significant role in the health policymaking, it is necessary to incorporate the hypothesis that assumes the causal links between the differing medical professional power and the vrying scope of public health. Following this view, this paper examined the various hypothese, including the power of medical profession, and found that the variables related to medical professional power as well as social democratic perspectives are its significant factors. In particular, our result shows that the power of medical profesion is the most important determinant, thereby supporting the hypothesis developed in this paper.