The present study examined the gills and liver histopathology of the freshwater fish chub caught from three different sites (Site A: Askale, Site D: Dumlu, and Site S: Serceme) in the Karasu River. At Site A, the concentrations of some metals such as cadmium, aluminum, arsenic, lead, and manganese exceeded acceptable levels according to the Turkish Standards Institute. Moreover, the concentrations of metals in the liver and gills of the collected fish were determined. The presence of histological alterations was assessed by the degree of tissue change. The quantitative histological assessment indicated that the histological lesions were comparatively most severe in the liver. The results revealed that anthropogenic pollution of aquatic ecosystems affected the fish in their natural habitat.