OBJECTIVE To compare the effect of two dose regimes of IVIg (0.5 g/kg vs. 1g/kg given soon after birth) on duration of phototherapy in Rh-isoimmunized neonates 32 week and above gestation. METHODS Randomized controlled trial. METHODS Tertiary care hospital. METHODS Rh positive blood group neonates of gestation 32 weeks and above born to Rh negative mothers having positive Direct Coombs test and without any major malformation. METHODS Intravenous immunoglobulin (IVIg) infusion over 2 h either 0.5 g/kg (low dose group, n=19) or 1.0 g/kg (high dose group, n=19). METHODS Duration of phototherapy. RESULTS The mean duration of phototherapy was 77.3+/-57.2 h in low dose group versus 55.4+/-49 h in high dose group (mean difference=21.9; 95% CI-13.1 to 56.9). There was no difference in need for exchange transfusion (21% in both the groups) and requirement of packed red blood cells transfusion (12 transfusions in both groups). The duration of hospital stay was similar [8.4+/-6.9 and 13.6+/-14.8 days, respectively (mean difference=-5.1; 95% CI-12.8 to 2.5)]. No adverse effects of IVIg administration were noted. CONCLUSIONS Two regimens of IVIg (0.5 g/Kg or 1 g/Kg) had comparable effect on duration of phototherapy, duration of hospital stay and exchange transfusion requirement, in Rh isoimmunized neonates of gestation 32 weeks and above.