The present study was carried out in Mariout Lake, which considered an important natural resource for fish production in Alexandria governorate, Lake Mariout is surrounded by different sources of pollution, such as sewage, industrial and agriculture drainages. Therefore, the present study was conducted in five sites to evaluate the effects resulting from pollution on the physical and chemical properties of water. Water samples were collected monthly to investigate the effect of different geographical seasons (winter, spring, summer and autumn) of 2018. Obtained results revealed that pH values reached an increased value of 8.8. The highest values of total alkalinity and total hardness were 465.8 and 5400 (mg/l as CaCO3), respectively. The highest values of NO2, NO3 and total nitrogen that recorded alongside the study period were 0.2, 2.32 and 3.98 mg/l, respectively. The highest recorded values of PO4 and total phosphorous were 0.42 and 0.92 mg/l, respectively. Depending on the increased values of nutrients and chlorophyll 'a' (459.6 µg/l), as well as dissolved solids, some basins of the lake classified as eutrophic while the other basins classified as hypertrophic.