A series of overlapping decapeptides (offset by five amino acids) were synthesized on the basis of the sequence of β-lactoglobulin. Two IgG-binding epitopes were identified using individual sera from cow milk allergic patients, which located in the sequence of aa22-36, aa127-141, respectively. The results indicate that it is feasible to decrease the allergenicity of cow milk by hydrolysis which specially destroy the epitopes of β-lactoglobulin.Key words: cow milk; β-lactoglobulin; IgG; epitope