Management of dairy whey has often involved implementation of the most economical disposal methods, including discharge into waterways and onto fields or simple processing into low value commodity powders. These methods have been, and continue to be, restricted by environmental regulations and the cyclical variations in price associated with commodity products. In any modern regimen for whey management, the focus must therefore be on maximizing the value of available whey solids through greater and more varied utilization of the whey components. The whey protein constituents offer tremendous opportunities. Although whey represents a rich source of proteins with diverse food properties for nutritional, biological, and functional applications, commercial exploitation of these proteins has not been widespread because of a restricted applications base, a lack of viable industrial technologies for protein fractionation, and inconsistency in product quality. These shortcomings are being addressed through the development of novel and commercially relevant whey processing technologies, the preparation of new whey protein fractions, and the exploitation of the properties of these fractions in food and in nontraditional applications. Examples include the following developments: 1) whey proteins as physiologically functional food ingredients, 2) alpha-lactalbumin and beta-lactoglobulin as nutritional and specialized physically functional food ingredients, and 3) minor protein components as specialized food ingredients and an important biotechnological reagents. Specific examples include the isolation and utilization of lactoferrin and the replacement of fetal bovine serum in tissue cell culture applications with a growth factor extract isolated from whey.