Various whey products were studied for the degree of protein denaturation and their protein nutritional qualities. The biological value and true digestibility of the proteins were high in all products although the individual whey proteins showed varying degrees of denaturation. Furthermore, all whey products contained a surplus of available lysine as compared to the lysine content of the Food and Agriculture Organization reference amino acid pattern. We concluded that the protein nutritional quality of the whey products was sufficient to be of nutritional significance in human diets.