BACKGROUND The classical response to nerve stimulation may be altered in cases of radial club hand. Ultrasound guidance may prove to be a useful tool in such situations. In this study, we compared the success rate of ultrasound-guided infraclavicular brachial plexus block with nerve stimulation for children undergoing radial club hand repair. METHODS Fifty children, aged 1-2 yr, undergoing radial club hand repair were randomly assigned to receive infraclavicular brachial plexus block guided by nerve stimulator (Group NS) or ultrasound (Group U) in combination with light general anesthetic. Bupivacaine 0.5 mL/kg of 0.5% was injected in both groups. Pain response to surgical stimulus was considered as block failure. The Children's Hospital Eastern Ontario Pain Scale pain score was recorded at 1, 4, 6, 8, and 10 postoperative hours. RESULTS In Group NS, the blocks were successful in 16 of 25 patients (64%), whereas in Group U, 24 of 25 patients had successful blocks (P = 0.0053). There was no difference in the time to first analgesia or analgesic consumption in the 10-h study period. CONCLUSION Ultrasound-guided infraclavicular brachial plexus block improves the success rate in patients with radial club hands when compared with nerve stimulation in patients undergoing radial club hand correction.