In the present study, histopathologic effects of the cement mixing with water in aquatic environment on rainbow trout (Oncorhynchus mykiss) and Siberian sturgeon (Acipenser baerii) has been examined. Both of the two fish species were exposed to 125 and 500 mg/l of concentrated cement for 96 hours. LC50 values were calculated 0.44 g/l for trout (O. mykiss) and 0.62 g/l for Siberian sturgeon (A. baerii) at the end of the experiment for 96-hour test period. No mortality was observed in control groups. Multiple deformations became remarkable in the gills of both species. However, some hyperplasia was observed on secondary lamellae of gills of both fish species. Hyperplasia rates were found to be much higher in the sturgeon individuals than the trout individuals. Also, lamellar fusion was another important pathology in the gills of the sturgeon individuals. Few necroses have been encountered on the lamellas of the trout gills. Multiple fat granules were observed in the trout liver tissue, melanomacrophage centers and necrosis on sturgeon liver tissue treated with 500 mg/l cement. As a result, this study expressly shows that both of the two species, Siberian sturgeon and rainbow trout, cannot tolerate cement-sourced contamination.