['Supraclavicular brachial plexus blocks are not common in children because of risk of pneumothorax. However, infraclavicular brachial plexus blocks have been described in paediatric patients both with nerve stimulation and ultrasound (US)-guidance. US-guidance reduces the risk of complications in supraclavicular brachial plexus blocks in adults.', 'To compare the success rate, complications and time of performance of US-guided supraclavicular vs infraclavicular brachial plexus blocks in children.', "Eighty children, 5-15 years old, scheduled for upper limb surgery were divided into two randomized groups: group S (supraclavicular), n = 40, and group I (infraclavicular), n = 40. All blocks performed were exclusively US-guided, by a senior anaesthesiologist with at least 6 months of experience in US-guided blocks. For supraclavicular blocks the probe was placed in coronal-oblique-plane in the supraclavicular fossa and the puncture was in-plane (IP) from lateral to medial. For infraclavicular blocks the probe was placed parallel and below the clavicle and the puncture was out-of-plane. Ropivacaine 0.5% was administered up to a maximum of 0.5 ml x kg(-1) until appropriate US-guided-spread was achieved. Block duration and volumes of ropivacaine used (mean+/-1SD) in the supraclavicular approach were recorded. Success rate (mean +/- 1 SD, 95%confidence interval), complications rate and time to perform the block (two-tailed Student's test) were recorded both for supraclavicular and infraclavicular approaches.", "In the US-guided supraclavicular brachial plexus blocks, the duration of the sensory block was 6.5 +/- 2 h and of the motor block was 4 +/- 1 h. The volume of ropivacaine used in this group was 6 +/- 2 ml. In group I, 88% of blocks achieved surgical anaesthesia without any supplemental analgesia compared with 95% in group S (P = 0.39; difference=7%; 95% CI: -10% to 24%). Failures in group I were because of arterial puncture and insufficient ulnar or radial sensory block. Failures in group S were because of insufficient ulnar sensory block. No pneumothorax or Horner's syndrome was recorded in either group. The mean time (SD) to perform the block was in group I: 13 min (range 5-16) and in group S: 9 min (range 7-12); the 95% CI for this difference was 2-6 min and was statistically significant (P < 0.05)."] Does ultrasound-guided supraclavicular vs infraclavicular brachial plexus block in children?