The mosque of Al-Nasir Mohammad Ibn Qalawun represents one of the important and high valuable Mamluk mosques in Egypt. The granitic columns used in this mosque provide a significant case of reusing the architectural elements dated back to the earlier Pharaonic constructions. These granitic columns have been exposed to aggressive physiochemical and mechanical weathering processes. Moreover, they have been subjected to faulty restoration with an inappropriate resinous material which led to many deterioration aspects. The current study aims to assess the state of granitic columns and to characterize their deterioration aspects. Examinations and analytical study were carried out using stereomicroscope (SM), scanning electron microscope (SEM), polarized light microscope (PLM), X-ray diffraction analysis (XRD), energy dispersive spectrometer (EDS), Brunauer-Emmett-Teller surface area (BET), Raman spectroscopy (RS), in addition to microbiological investigation. The data declared conversion of mineralogical composition, discoloration, poor aesthetic properties, increase of porosity, cracks, surficial flaking, salt crystallization and microbiological colonization. Hence, it is crucial to conduct conservation of the studied granitic columns.