BACKGROUND: Primary cleft lip repair is performed in infants under 1 year of age. The efficacy of an infraorbital nerve block vs intravenous fentanyl was compared in our prospective, randomized controlled trial. METHODS: Forty-six infants scheduled for primary cleft lip repair were prospectively randomized to one of two groups: group F that received 2 mcg x kg(-1) of fentanyl intravenously and an infraorbital nerve block with 0.5 ml on each side of preservative-free normal saline, and, group B that received bilateral infraorbital nerve blocks with 0.5 ml on each side of 0.25% bupivacaine and 2 ml of preservative-free saline solution intravenously after induction of anesthesia but prior to surgical incision. Patients were observed by a blinded observer for (i) pain scores using neonatal infant pain score; (ii) need for rescue medication in the anesthesia care unit (PACU), in the short stay unit (SSU) and at home and (iii) feeding parameters including difficulty in feeding, time to first feeding and volume of feeds in the PACU, SSU and at home. RESULTS: There were no significant differences in pain scores between the two groups over time (P = 0.98); there were no differences between groups in the number of rescue medications in the PACU, in the SSU as well as at home; however, the time to first rescue medication was greater in the block group compared with the fentanyl group (P = 0.07). There were no significant differences in feeding volumes between groups in the PACU (P = 0.46), SSU (P = 0.57) and at home (P = 0.15). There were no differences in time to initiate feeding between the two groups (P = 0.81). However, there was difficulty with feeding in the block groups compared with the fentanyl group (P = 0.01). CONCLUSIONS: The infraorbital nerve block can be effectively used for pain control in infants undergoing primary cleft lip repair. Although children undergoing a nerve block experienced minor difficulties in feeding, there were no differences in feeding volumes or other feeding parameters. This study has shed light into postoperative outcomes besides pain control on children undergoing cleft lip repairs.