Objective Mycoplasma gallisepticum causes chronic respiratory disease in chickens and sinusitis in turkeys and have been a major problem in the poultry industry throughout the world for many years.It is the most pathogenic and economically significant mycoplasma pathogen of poultry.Live M.gallisepticum vaccine is an approach to reduce susceptibility to infection and to prevent the economic losses, appear to be more effective and popular than bacterins.