A total of 36 milk samples obtained from Egyptian buffaloe's and Friesian cow's were used to investigate the serum protein fractions. Milk serum protein were obtained after removal of casein from skim milk through precipitation in the isoelectric point. Partition of serum protein by electrophoretic technique revealed four distinct frac tions named as serum albumin, beta-lactoglobulin, alpha-lactalbumin and immune-globu lins. Variations in the concentration of serum protein fractions are distinctly present in both cow's and buffaloe's milk specially in beta-lactoglobulin and immune-globulin content. Insignificant differneces could be detected in the concentration of the var ious fractions between the individual and composite milk samples.