With respect to the medical cost issue in current controversy in the field of social welfare, the best solution for our community could be sought by taking approaches balancing the principle of private autonomy and social solidarity doctrine. In this context, we need to review the introduction process and the implementation details of the Patient Protection and Affordable Care Act in the United States. Although there are some assertions claiming that the United States adopted the universal social welfare regime in the field of medicine via enactment of the Act, the real purpose of the Act is to maintain its selective social welfare system under the principle of private autonomy through assuring the freedom for selecting private insurance contract parties and conditions, imposing the responsibilities to be healthy as possible as they can on their people, differentiating volume of subsidies according to annual incomes and prohibiting the government from adopting any uniform index standards such as QALY. Like the United States, in South Korea, it is required to strike balance between the principle of private autonomy and the solidarity doctrine by restoring the status and position of self governing rule in the field of medicine to improve health conditions of our people through their self management, enhance quality of medicine by conducting more creative treatment measures and more efficiently allocate limited medical resources to more required patients.