Chicken egg yolk antibodies were raised in 24 week old white leg horn chicken against mastitis causing Escherichia coli. Booster injections of increasing concentrations of antigen were given to raise the antibody level in egg yolk. The antibodies were purified from immunized chicken egg yolk by Polson et al.(1980) and further purified by DEAE cellulose ion exchange column chromatography. High titre of more than 1:10000 antibodies were detected by ELISA at 150th day of observation. IgY concentration varied in the range of 0.5 – 7.1mg/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 E.coli culture. The results indicate that antibodies generated in chicken could be used for Diagnosis and therapeutic purposes in case of bovine mastitis.