Copyright © 2018 by Türkiye Klinikleri.Cystic fibrosis (CF) is usually presented with pulmonary symptoms and failure to thrive. Severe anemia as the initial symptom of CF is reported exceptionally. Herein we described a six-month-old CF patient who admitted to another care center with severe anemia when she was three month-old. She was referred to another center due to pallor and edema as she was 3 month old. Laboratory data revealed hemoglobin: 5,5 g/dL, albumin: 1,5 g/dL. Cow's milk allergy was her initial diagnose. Hypoallergenic milk formula and vitamin was added to the child’s diet. The patient was admitted to our center because of no clinical improvement with this diet. Due to respiratory complaints and severe malnutrition at her admission, CF was suspected. This was confirmed by a high level of sweat chlorine (110 mEq/L). The aim of this case report is to emphasize that in early infancy severe anemia can be the first sign of CF before respiratory symptoms occur.