The main elements of milk proteins can be summarized as follows: variable phosphorylation degree of the four caseins, variable glycosylation of ?-CN and ?-La, frequent presence of casein peptides generated by the action of endogenous and bacterial enzymes, wide molecular mass range whey proteins, easy thermodenaturation of whey proteins. With more knowledge of the primary structure, the location of the phosphate groups on the casein chains, and intra-and inter-protein disulphide bond exchanges during milk processing, particularly during digestion by proteolytic enzyme, the function and the role of most important milk proteins are now better understood. Further insight into the basic properties of milk proteins should lead to a greater understanding of the natural function of milk and the roles its components play in human nutrition. In this paper milk proteins are reviewed in the perspective of preventing milk allergies in newborns.