With the industrialization of societies, population growth, climate change, and increased exploitation of surface waters, environmental pollutants have increased, leading to a decrease in the quality of existing water resources. Therefore, examining the quality of river pollution is of great importance for agricultural and environmental programs. In order to investigate the water quality of the Tigris River using 4 biological indicators, sampling was carried out from April 2021 to March 2022 and the above indicators were calculated based on the data obtained. After identifying and determining sampling stations, biological indicators were calculated to determine the level of pollution in this river. The results showed that the average NAFWQI index indicated poor water quality, the BMWP index indicated moderate and poor water quality, the ASPT index indicated suspected pollution and pollution with medium levels, and the Helsonhof index indicated relatively poor and poor water quality. Based on the results of this study, most of the examined indicators show that Tigris River's water quality is in a low to moderate category