aying attention to security is one of the requirements of every state. The modernist state of First Pahlavi seriously considered social security from its own perspective. The aim of this research is to describe and analyze social security in the First Pahlavi era. The method is qualitative and historical-analytical one. By using written sources, this research deals with the question: Given the economic, social and cultural policies of First Pahlavi modernist state, how was social security in that era? The findings indicate that in the First Pahlavi era, the most significant task of modernist state, particularly police forces (Shahrbani), was to support absolute power of monarchy and preventing from every kind of political and social movements and legitimate freedoms. It was organized in a way that up-down policies and authoritarian measures of the regime could be implemented in social, economic and cultural dimensions, particularly weakening clergymen, uniform clothes, eliminating Islamic veils, anti-religion measures including destroying religious identity and culture, formal parliament, press censorship, property arrogation, horrible security organizations and so on, were not only the sources of fear and suffocation in society but also indicated the lack of social security in the First Pahlavi society.