Chicken Egg Yolk antibodies (IgY) were raised in 24 week old white leg horn chickens against Streptococcus mitis (MTCC 2696). The chickens received Booster injections of increasing concentrations of antigen to raise the antibody level in egg yolk. The anti-bodies were purified from immunized chicken egg yolk by Poly ethylene Glycol (PEG) and Ammonium sulphate precipitation method and further purified by DEAE cellulose ion exchange column chromatography. High titre of more than 1:10000 antibodies were detected by Indirect antigen capture ELISA at 150th day of observation. IgY con-centration varied in the range of 0.85 – 7.6mg/ml of yolk throughout the immunization period. Growth inhibition assay showed the absence of growth when the specific egg yolk antibodies was added to the Streptococcus mitis culture. Inhibition ELISA shows decrease in absorbance with increasing concentration of IgY. The results indicate that antibodies generated in chicken could be used for diagnosis and therapeutic purposes in case of Streptococcus mitis.