The dairy industry generates increasedamounts ofwhey fromboth cheese and casein production facilities.Whey
presents an elevated content of lactose and proteins, which are associated with its high biological oxygen
demand and decomposing potential. Despite its potential as pollutant, whey has been considered as a dairy
by-product due to its nutritional, functional and bioactive properties. The use of enzyme technology may be an
interesting strategy to convert whey into added-value products. The hydrolysis of whey proteins can generate
bioactive peptides, which are described to perform physiological effects in vivo, such as antioxidant, antimicrobial,
antihypertensive and antidiabetic activities. Bioactive peptides derived from whey proteins have been
also associatedwith immunomodulatory, anticancer, opioid and hypocholesterolemic activities. This reviewpresents
a discussion on the main biological activities of peptides derived from whey proteins.