This article investigates the problem of changing land uses in historical city centers, a problem which often leads to the alteration of their historical, architectural and functional physiognomy, as well as the loss of their inhabitants. It also discusses the importance of land management and proposes a multifunctional reuse model for sustainable development in abandoned or degraded areas in historic cities. This problem is found in historical centers nowadays, especially in the European South, and many theoretical texts and urban studies deal with the issue. Taking under consideration the case of the Historical “Commercial Triangle” of Athens, this article presents the results of an extensive field work, which led to the mapping and analysis of the neighborhood’s special identity. Subsequently, these results lead to the presentation of the problems caused by the dominating uses of recreation and tourism, which suppress the traditional existing commercial uses and the residency. It concludes by proposing preservation strategies for the reuse and development of the area and emphasizes the importance of a management plan aiming towards the preservation of the historical character of the commercial center and its sustainable development. The work presented in this paper is based on an assignment produced in 2020 for the purposes of the post-graduate course “Protection and Preservation of a historical urban center or settlement”, which is part of the post-graduate program “Protection of Monuments” in the School of Architecture, NTUA.