The main goal of this doctoral thesis is the analysis of semiotic and diachronic changes in the street names of selected city districts of Osijek during the 20th century, through the use of available archival cartographic maps. Cartographic maps are the key to the analysis of specific changes in street names, since cartographic maps can be viewed as a paradigm of historical and contemporary situation, which provide insight into the existence of multiple worldviews of a particular historical and ideological period. Street names of a certain historical period are semiotic signs of that period. Changes in street names testify changes in the regime, which lead to the ideological reorientation of society and a gradual change in the identity of the city and thus its inhabitants, also they testify changes in semiotic signs. Available analogue cartographic maps of the city of Osijek, which are stored in the State Archives in Osijek, were digitized and provide a basis for analysis of spatial and temporal changes in street names caused by historical and ideological changes, including six different observed periods. Spatial-temporal changes of street names from digitized cartographic templates were analyzed using GIS tools, analyzing changes within the following six periods: Austro-Hungarian Monarchy, Kingdom of Yugoslavia, Independent State of Croatia, Federal People's Republic of Yugoslavia, Socialist Federal Republic of Yugoslavia and Republic of Croatia. The State Archives in Osijek, as the main heritage institution of the eastern part of the Republic of Croatia, preserves collections of cartographic maps of the city of Osijek from all the above mentioned periods. The dissertation processes one selected cartographic map per observed period and compared it with the current situation, ie today's street names, taken from the official website of the city of Osijek. The analysis of changes was conducted within the following three city districts: Tvrđa, Gornji grad and Donji grad, as they are the oldest city districts, whose streets existed in all analyzed periods. In addition to the frequency of changes in street names, the dissertation deals with different categories of names, which were in use in certain periods. The analysis shows how much historical and political changes influenced the semiotic changes of street names in a certain period and how much a certain political regime, through changes in street names, ie semiotic signs of the regime, tried to impose its ideology and influence the identity of the city and its inhabitants.