This study was carried out during period extended from January 2013 to December 2013 to evaluate the microbiological and physicochemical characteristics of Rosetta branch water, River Nile. The examination includes eight locations along Rosetta branch. Temperature values were ranged between 17.6 to 31.0ºC while, pH values ranged between 7.16 to 7.98 during four seasons. Moreover, turbidity values were ranged between 1.90 to 33.7 NTU during all seasons. Regarding dissolved oxygen (DO) value, the lowest (3.1 mg/l) and the highest (8.0 mg/l) values were recorded during autumn and winter, respectively. Moreover, the highest (26.6 mg/l) and the lowest (3.30 mg/l) values of biological oxygen demand (BOD) were recorded during winter and autumn, respectively. Chemical oxygen demand (COD) values were ranged between 7.4 to 42.6 mg/l which recorded during winter season. Additionally, ammonia values were ranged between 0.22 to 7.70 mg/l during all four seasons. Nitrite values ranged between 0.002 to 0.071 mg/l during all four seasons. The lowest nitrate value (0.10 mg/l) and the highest value (1.02 mg/l) were recorded during summer and winter, respectively. Respecting the monthly changes in microbial counts of Rosetta branch, average log no. of total coliform was ranged between 1.84 to 6.88 CFU/100ml, the highest log no. in most locations were recorded during July. While, average log no. of fecal coliform was ranged between 1.30 to 6.5CFU/100ml during all months. Moreover, the highest counts of log no.  was (5.96 CFU/100ml) and the lowest log no.  was (0.30 CFU/100ml) of E. coli   were recorded during August. Additionally, the highest log no.  of fecal streptococci (4.85 CFU/100ml) was recorded during July.