Cow's milk allergy is the most common food allergy in children. Casein, whey, alpha-lactalbumin, beta-lactoglobulin and bovine gamma-globulin are the best known allergens in cow's milk. Herein, we present an infant who was diagnosed with severe cow's milk allergy, followed-up with an elimination diet, and experienced a life-threatening severe anaphylaxis after live attenuated measles vaccine containing alpha-lactalbumin hydrolysate. high levels of immunoglobulin E (IgE) antibodics were determined by specific IgE analysis and the sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) method. It might be dangerous to administer live attenuated measles vaccine to children diagnosed with cow's milk allergy or to children suspected of being highly sensitive to cow's milk proteins.