this Study indicate various efficacy of commercial disinfected against Newcastle virus in absence and presence of organic matter at different contact times. Four commercial disinfectants were tested against selected viral isolates. The obtained result revealed that the tested disinfectants were effective at absence of organic matter. While, in presence of organic matter longer contact time were required to decrease effectiveness of Newcastle disease virus. Regular monitor program should be taken in poultry farm to test the problematic virus individually for resistance against commercial disinfected.
Key words: Disinfectant, virus, resistance, isolates