This study was conducted to compare the efficiency of three commercially available disinfectants (Virkon S, T.H5 and Np50) against 3 bacterial isolates from New-valley broiler farms (Salmonella typhimurium, E. coli and Staph. aureus) in vitro. The evaluation was conducted at three consequent contact times 5, 15, 30 min. All tested disinfectants were diluted with sterile distilled water and applied at three different concentrations. The concentrations used were the manufacturer's instruction beside a higher and lower one. At the recommended concentration by the manufacturer, the most powerful disinfectant against all tested organisms was TH5 followed by Virkon S. On the other hand, NP50 was the weakest disinfectant. At 5 minutes, the reduction log showed by TH5 on S. typhimurium, E. coli, and S. aureus were, 3.6, 2.55, 3.54, respectively. Moreover, the reduction log for Virkon-S were 3.02, 2.21, and 3.37 on S. typhimurium, E. coli, and S. aureus, respectively. On the other hand, the reduction log induced by NP50 were,1.76, 1.91, 3.37 on S. typhimurium, E. coli, and S. aureus, respectively. At 15 minutes, the reduction log showed by TH5 on S. typhimurium, E. coli, and S. aureus were, 4.97, 3.59, 4.11, respectively. Moreover, the reduction log for Virkon-S were 4.97, 3.31, and 5.19 on S. typhimurium, E. coli, and S. aureus, respectively. On the other hand, the reduction log induced by NP50 were,2.82, 1.82, 4.27 on S. typhimurium, E. coli, and S. aureus, respectively. After 30 minutes, no growth was observed for S. aureus with 100% inhibition for TH5 while the reduction log for S. typhimurium, E. coli were, 7.32 and 7.16, respectively. Concerning Virkon-S the reduction log was, 6.5, 4.67 for S. typhimurium, E. coli, respectively while, S. aureus were completely inhibited with 100% inhibition. On the other hand, the reduction log induced by NP50 after 30 minutes were, 5.93, 3.4, 7.35 for S. typhimurium, E. coli, and S. aureus, respectively.