Tylvalosin tartrate is a macrolide antibiotic that has antibacterial activity against Gram-positive, some Gram-negative organisms and mycoplasma. It acts by inhibiting protein synthesis in the bacterial cell. Mycoplasma gallisepticum causes chronic respiratory disease (CRD) of domestic poultry, especially in the presence of management stresses and/or other respiratory pathogens. Disease is characterised by coryza, conjunctivitis, sneezing, and by sinusitis, particularly in turkeys and game birds. It can result in loss of production and downgrading of meat-type birds, and loss of egg production. In the current study, effect of tylvalosin on performance parameters (body weight gain, feed consumption as well as feed conversion ratio), hematological and biochemical profile were studied. A total of 24 fourteen-day old broiler chicks were divided into 3 equal groups. G1; control (-ve) group, G2; control (+ve) group that experimentally infected by mycoplasma gallisepticum at 30th day of age by intraocular/intranasal and intra tracheal rout, G3; experimentally infected by mycoplasma gallisepticum at 30th day of age by intraocular/intranasal and intra tracheal rout then received 25 mg/kg of tylvalosin per os for five consecutive days beginning from the 7th day of infection. In conclusion, treatment with tylvalosin at dose 25 mg/kg for consecutive 5 days was significantly improved growth performance (increased weight gain and feed utilization efficiency) with hematological and biochemical alteration and at least alleviate or partially reduce the severity of chronic respiratory disease (CRD) induced by Mycoplasma gallisepticum in broiler chickens.