The article presents the spatial-functional transformations of a medium-sized post-industrial city in the context of the decline in the industrial function which used to occupy a prominent position in the city. The research attempts to answer the following questions: (1) What has been reflected in the spatial and functional development of the city and its landscape by the dynamic transformations in the industrial sector that have taken place since the 1970s, playing out in the broad context of the specific political and socio-economic conditions? and (2) how is the city dealing with post-industrial sites—are we dealing with a ‘post-industrial scar’ or a process of their adaptation to the needs of the present? Analyses were initiated to identify differences in spatial and landscape structure from 1966 to the present. To this end, a land cover analysis was carried out based on available sets of aerial photographs taken in four selected years within the study period, as well as a calculation of the index of variation. Graphical and GIS software (QGIS 3.28.4 version) and methods of statistical data analysis were used. To come up with a full picture of transformations in the second half of the 20th century, an outline of the historical spatial development of Gorlice and the local oil and engineering industry was presented. The results of the research confirm the relationship between the functional and spatial development of the city and the transformation and condition of its industrial function.