In his thesis, author elaborates and analyzes historical and urban development of Zagreb city district „Trnje“ and its transformation into urban city area. The district represents an integral part of the city of Zagreb, but it was never fully integrated into the urban area due to its specific development issues. First part of the thesis deals with historical development of the district, impact of industrialization on its modernization and the beginning of reconstruction of Zagreb after World War II. Second part of the thesis deals with postwar urban planning of Trnje area and its construction into a new city center. The main body of the thesis is divided in two parts: first, in which the author elaborates on urban plans and programs of Trnje, which he then compares with achieved results of its longstanding construction in the second part of the thesis. Special attention is drawn to the relationship between the new government and Trnje which, as a worker's settlement, was supposed to become a new city center. This relationship needs to be observed through ideological prism in which the Communist Party identified the construction of Trnje with the construction of a new society and order. Therefore, this thesis represents the analysis of socio-political relations and its impact on architecture and urbanism of the city of Zagreb in the period from the end of World War II all the way to the dissolution of SFRY.