IgE binding antigen of the major proteins in egg white, which is hen (H), quail (Q) and duck (D) was determined using the sera of patients with egg allergy. The major proteins of egg white were ovotransferrin (OT), ovoinhibitor (OI), ovalbumin (OA), ovomucoid (OM) and lysozyme (LY). The age of egg allergy patients is used this present studey were 3 years 4 months-old to 4 months-old (RAST 2~6). After SDS-PAGE analysis of egg whites, Western-blotting and enzyme-immunoassay was examined using the serum of 33 patoents with egg allergy. The positive blots of IgE binding proteins were ranked score 1~5 by positive color. The blots from score 2 to score 5 were positive of IgE binding. The positive percent of IgE blotting to hen OM was shown to have higher positive percent relatively to the other major proteins with the serum of 33 patients. And, on the sera of RAST 3 and RAST 4~6, ratio of IgE binding to hen OM indicated high positive percent. Therefore, from this study, these findings suppose that hen OM is the most important allergen of egg white proteins