The article is devoted to theoretical and methodological foundations of the study of the welfare state. The author identified the factors indicating the urgency of this issue. Special attention is paid to problems of genesis of social rights in particular. The important role of the constitutional recognition of social rights is highlighted. The author analyzed the social dimension of human rights and fundamental freedoms; and formulated the principles of the welfare state, i.e. principles of equality and justice, and explained their essence. To conclude, the author provided a personal view regarding theoretical and methodological foundations of social policy.