Diazinone & malathion bioremediation, in vitro study, was done in a liquid medium by soil isolated bacterial strains.  Malathion and diazinone residue concentrations were measured at interval times until 14 days after incubation. Results indicated that three isolates namely, F1, F3 and D3 showed high ability of degrading both diazinone & malathion with degradation ratio 35.8 , 56.1  and 29.8 %  respectively, for malathion and 33.6,  49.7 and 24.5 %  respectively, for diazinone, after 14 days of incubation. The best temperature for biodegradation was 30^oC for all isolates. While the best pH values for degradation were 7.0 for both Bacillus & Staphylococcus isolates and 7.5 for Pseudomonus . Also this study improved that the degradation percentages was better in case of the absence of other carbon source in the medium.