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) antibodies 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.