Aquatic insects are bioindicators of water quality be situated used in assessing the environmental integrity of streams. Their composition and density in Damietta Branch which one of two branches of the Nile River in Egypt was assessed and the influence of different pollutants in the water on their distribution during different seasons. Insects were sampled using standard entomological methods, while the physico-chemical parameters of the water were analyzed using APHA methods to estimate water quality parameters. Results of physico-chemical parameters revealed that almost all measurements are fall within the permissible limits. A total of 2,847 aquatic insects was sampled throughout the studied period among all sites, 19 families belonging to seven insect orders were identified. The richness of the aquatic insects was affected by the nature of the substrate, macrophytes, and anthropogenic activity in the water stream. The results show that low varieties of species were observed in sites (4, 5, and 6) than in sites (1, 2, and 3).