Fresh milk samples were heated at 65℃, 75℃, 85℃, 95℃ and 105℃ for 15 minutes to define the heating effect for denaturation of whey protein. When whole milk was heated at 85℃ for 15 minutes, the β-lactoglobulin was disappeared from the fraction of whey protein, at 95℃ for 15 minutes, the α-lactalbumine was disappeared, and the other whey protein (serum albumine, immunoglobulin) was denatured at 75℃ for 15 minutes. Heat denaturation of whey proteins was sedimented with acid casein which coagulated with 1-N HCl solution (pH 4.6), so that denatured whey protein appeared in acid casein fractions.