Abstract: Phosphates solubilizing bacterial strains were isolated from various rice- rhizosphere soils of southern peninsular region of India. Thirty efficient PSB isolates were selected from 226 colonies based on their ability to form clear zone on Pikovskaya’s agar medium. Phosphorus release and phosphatase activity were quantified using ELISA on 3rd, 5th and 7th day of incubation to determine the efficiency of the strains. The isolated phosphate solubilizing bacterial strains released high amount of phosphorus from tricalcium phosphate and ranged from 22.4 to 825.8 μg P mL-1 and the amount of phosphatase secreted into the medium ranged from 11.6 to 64 U. From the results we conclude that the efficiency of the strain to solubilize phosphate or release phosphorus depends on the specificity of the enzyme phosphatase than the amount of phosphatase released into the medium. The efficient strains isolated from rice rhizosphere soils were identified as Enterobacter, Micrococuss, Pseudomonas, Bacillus, Klebsiella and Serretia. Among all the strains, A4 strain (Enterobacter aerogenes) released high amount of phosphorus. All the isolated PSB were efficient phosphate solubilizers and can be used as bioinoculants to increase the available phosphorus in the soil for rice plant growth.