Three newborn infants who developed hyperbilirubinemia due to blood group incompatibility were treated with high-dose gammaglobulin. Hyperbilirubinemia was caused by Rhesus (Rh) incompatibility (anti-E + anti-c) in Infant 1 and ABO incompatibility (anti-B) in Infants 2 and 3. Hyperbilirubinemia was refractory to conventional phototherapy but responded well to intravenous gammaglobulin (IVGG) at a dose of 1 g/kg in all infants. No adverse effects were observed. These findings suggest that high-dose IVGG may be useful in the treatment of hyperbilirubinemia due to isoimmune haemolytic disease resistant to phototherapy.