Milk is a major source of nourishment in an infant’s diet. Milk contains two major types of unique proteins namely whey protein and casein. Both the proteins are nutritionally important as whey protein provides high amount of branched chain amino acids and the casein fraction provides essential amino acids. However, qualitative differences in these two types of proteins have led to the debate regarding superiority of one over the other. Mounting evidence indicates that whey protein offers various nutritional and immunological benefits over casein. This issue of ‘Myths and Facts’ series on ‘Whey Protein’ will help burst several misconceptions regarding the use of whey proteins for infant nutrition.