The aim of this study was to understand of diversity and activity of dominant bacterial populations in the rhizosphere of rice. Two sites at different altitudes were selected in this study. A total of 335 isolates were recovered from irrigated and rainfed rice plants rhizosphere from both altitude. In which Bacillus sp. (27%) was found to be dominant followed by Pseudomonas sp. (26%), Azotobacter sp. (5%), Flavobacterium sp. (7%), Serratia sp. (4%) and Klebsiella sp. (6%). Enterobacter sp., Micrococcus sp. and Staphylococcus sp., were also observed in the isolates though in low frequency. Genera identified in rhizosphere isolates were also found in the rhizoplane. The spread plate technique was used to isolate and purify all the isolates. The characteristics of the bacterial strains were determined using the colony morphology, gram staining as well as biochemical properties. All isolates were screened for plant growth promoting activities such as siderophore production, indole-3-acetic acid production and phosphate solubilizaton. The lowest Shannon-Wiener index was 1.663 from Jangal rainfed rice and highest was 2.164 from Suddhowala irrigated rice field of Dehradun.