Aim: To evaluate HIV transmission in exclusively breastfed babies along with the ARV drugs. Material and method: The present study was conducted among 30 pairs of mother and infant in the Department of Pediatrics, University College of Medical Sciences and associated Guru Teg Bahadur Hospital, a tertiary care centre in Delhi. CD4 cell count and viral load using RT PCR was done at the time of presentation in all these unbooked HIV positive mothers. These mothers were started on triple drug ART at the time of delivery. Follow up visits were done at 6, 10, 14 weeks and 7.5 months of age to ensure drugs and feeding compliance. Results: Mean + SD of CD4 cell count at the time of delivery of mothers who were on ART was 404±189.62 and of those in ARV group was 507±120.16 with statistically insignificant difference. The overall risk of HIV transmission (ante, intra and postpartum) in babies born to HIV positive mothers at 6 weeks of age was 30% (9/30). At the end of study, overall HIV transmission rate in infants born to HIV infected mother was 36.7% (11/30). Conclusion: Triple drug antiretroviral therapy is effective in reducing transmission of HIV through breastfeeding in unbooked mothers even when started at the time of the delivery.