Modernism has emerged as an enlightenment project. It argues that the objectivity of the natural sciences and social sciences. It gives great importance to a developed economy, administrative rationalization and the differentiation of the world in a social sense. It takes into bureaucratic rules, the integrity and standardization within the public administration. It thinks that a hierarchical, process-oriented, centralized administrative structure. Generally, postmodernism is a reckoning with modernism. Postmodernism is a thinking way which questions the main concepts of modernism. It allows to some social arrangements focuses on individual preferences. According to the postmodernists, individual differences create a whole and there is no single explanation for the social realities. Postmodernism aims to reduce bureaucracy and red tape in the public administration. The main features of the postmodern public administration are decentralization, flexibility, participation, ad hoc organizations, importance of human capital, taking advantage of information technology. This study tries to analyse modernism and postmodernism concepts in a sociological respect. In this study, the modern and postmodern public administrations are examined in a comparative perspective.