Water samples from the river Ganga at Tribeni, West Bengal, India were sampled monthly to enumerate total heterotrophic bacteria (THB) and phosphate solubilizing bacteria (PSB) between January 2011 and December 2011. THB was high in the month of March and PSB was high in the month of July. The population density of THB ranged from 4.84-5.84x104 cells/ml and that of PSB ranged from 2.14-2.72x102 cells/ml. A significant variation in the capacity to solubilize phosphorous by the isolates of PSB were noted. The phosphatse activity of the isolates exhibited that the strain RPSB6 (27.38 μmoles/g/h) had higher activity followed by the strain RPSB9 (20.92 μmoles/g/h).