Intravenous Immunoglobulin G (IVIG) therapy has been used as a component of the treatment of hemolytic disease of the newborn. There is still no consensus on its use in ABO hemolytic disease of the newborn routinely. The aim of this study is to determine whether administration of IVIG to newborns with ABO incompatibility is necessary. One hundred and seventeen patients with ABO hemolytic disease and positive Coombs test were enrolled into the study. The subjects were healthy except jaundice. Infants were divided into two groups: Group I (n = 71) received one dose of IVIG (1 g/kg) and LED phototherapy whereas Group II (n = 46) received only LED phototherapy. One patient received erythrocyte transfusion in Group I, no exchange transfusion was performed in both groups. Mean duration of phototherapy was 3.1 +/- A 1.3 days in Group I and 2.27 +/- A 0.7 days in Group II (p < 0.05). Mean duration of hospital stay was 5.34 +/- A 2.2 days in Group I and 3.53 +/- A 1.3 days in Group II (p < 0.05). Mean duration of phototherapy was 4.0 +/- A 1.5 days and 2.73 +/- A 1.1 days in double and single doses of IVIG respectively, and this was statistically significant (p < 0.05). IVIG therapy didn't decrease neither phototherapy nor hospitalization duration in infants with ABO hemolytic disease. Meticulus follow-up of infants with ABO hemolytic disease and LED phototherapy decreases morbidity. IVIG failed to show preventing hemolysis in ABO hemolytic disease.