The study is devoted to the analysis of the transformation of the social development of Ukraine and the determination of a system of target priorities designed to ensure the effectiveness and efficiency of state social policy. The research methodology is based on World Bank tools and official statistical observations of the Ukrainian State Statistics Service, as well as the Methodology for Comprehensive Poverty Assessment and Living Wage Methodology officially adopted in Ukraine. The research results indicate a critically high growth rate of poverty, the growing dependence of citizens of Ukraine on social support from the state. An analysis of social development also indicates a high level of deprivation poverty and its destabilizing dynamics. It was revealed that the dominant drawbacks of state regulation of the social sphere are the unformed normative and methodological support for monitoring and adjusting the levels of social standards, the absence of reforms in the systems of pension provision, education and science, medicine, housing, and communal services, and regulation of employment. So, institutional regulation of the parameters of the development of the social sphere in Ukraine is insufficient and does not provide a solution to the critical problems of the demographic crisis, labour emigration, poverty alleviation, and, therefore, is not able to ensure sustainable social and economic development of the state. The strategic priorities of the system and structural transformation of the social sphere of Ukraine are the formation and establishment of the composition and structure of the elements of the social sphere system, the creation of a full-fledged social infrastructure and the institutional environment for its functioning, which will create conditions for the realization of citizens' constitutional rights to social protection.