Introduction: Cow's milk allergy is the most common food allergy in children. Symptoms usually involve the skin and the gastrointestinal and respiratory tracts. Gastrointestinal tract manifestations of cow's milk allergy are nonspecific, and are the only type that can be diagnosed in all age groups. Here, we report a rare case of cow's milk allergy in an infant with hypoalbuminemia and malnutrition. Case Presentation: A nine-month-old girl was admitted to Dr. Sami Ulus maternity and children's health and diseases training and research hospital, Ankara, Turkey, in September 2013, for weakness and swelling of the legs that had endured for two days. She had bilateral pretibial pitting (+2) edema. Laboratory data revealed albumin at 1.7 g/dL; serum Na, K, urea, creatinin, and alanine-aspartate aminotransferase levels were normal. Her urinary analysis did not reveal proteinuria. Stool samples were normal, and stool steatocrite was negative. Anti-gliadin, anti-endomysium, and anti-tissue transglutaminase antibodies were negative. Cow's milk allergy was diagnosed due to cow's milk-specific IgE and skin prick test results. Conclusions: On rare occasions, cow's milk allergy presents with hypoalbuminemia. When diagnosis is delayed, this allergy may impair the growth and quality of life and may even be life-threatening.