Historical buildings provide important information about the culture, civilization, art and social structure of the period they belong to. However, structures that cannot keep up with social or technological changes, lose their functions and users over time, become idle and enter the process of extinction by being neglected. Its use with a new function in the protection of historical buildings is a very effective conservation method. With this method, the reopening of historical buildings in line with new needs in accordance with their original identity, architecture and location ensures that these buildings continue their existence by regular maintenance, and at the same time produces cultural and economic benefits. Within the scope of this study, the transformation of the Aya Yorgi Church in the city of Isparta in the historical process, the place of the building in the history of the city of Isparta, and the social and cultural characteristics of the people of Karaman, who are the users of the building, were determined by literature research. Architectural information such as the spatial features of the building, its façade features, the architectural fittings in its interior, its decorations, its structural structure and the building materials used, and its state of preservation have been determined by field researches and survey studies and conveyed with technical drawings and photographs. Considering all these features that create the architecture and identity of the building, suggestions have been made to protect this valuable cultural heritage through reuse with a new function, which is a very effective instrument of the sustainable conservation, in order to transfer it to future generations. [ABSTRACT FROM AUTHOR]