Hematemesis is a rare condition in infants and can be a symptom of cow's milk-induced hemorrhagic gastritis. Other clinical manifestations of cow's milk allergy are vomiting, malnutrition and anemia. The criteria for the diagnosis of cow's milk allergy includes elimination of cow milk formula resulting in improvement of symptoms, specific endoscopic and histologic findings as well as exclusion of other causes. Cow's milk allergy should be considered in the etiologic differential diagnosis of hematemesis and gastritis in infancy. We have experienced a 1-month-old female infant with hematemesis due to cow's milk-induced hemorrhagic gastritis, and report the case with a review of previously published cases.