We are reporting on four infants with cow's milk protein intolerance who presented with hypochromic anemia and occult gastrointestinal hemorrhage. Esophagogastroduodenoscopy revealed erosive gastritis or gastroduodenitis in all cases. Management with a cow's milk-free diet led to a favorable clinical and hematological outcome; the endoscopic inflammatory image disappeared after the cow's milk-free diet trial. Challenge with cow's milk led to gastrointestinal symptoms and to impaired D-xylose absorption. The data presented suggest that some patients with cow's milk intolerance may have gastroduodenitis resulting in occult gastrointestinal hemorrhage and hypochromic anemia.