On rationale for government intervention is the failure of competition in the market. Health care markets are characterized by such unique aspects as information asymmetry, prevalence of insurance, and cost-increasing competition based on the adoption of costly medical technology. Therefore, government policy to guarantee a sufficient number of providers in markets may not lead to socially beneficisal outcomes such as higher quantity and lower price. This paper examines the unique nature of health services and its implications for competition, the evidence that competition may not reduce health care ex[enditures, and policy tools that government can use to encourage competition which contributes to supporting a sustainable health care system.