Objectives:To compare the analgesic efficiencies of caudal blocks, ultrasound (US)-guided transversus abdominis plane (TAP) blocks, and ilio-inguinal/ilio-hypogastric (II/IH) blocks performed to provide postoperative analgesia in pediatric patients undergoing unilateral lower abdominal surgery.Methods:This prospective, randomized, single-blinded study was conducted in the Department of Pediatric Surgery, Faculty of Medicine, Gaziantep University, Gaziantep, Turkey from July 2013 to January 2015. The doses used were as follows: 0.5 ml/kg (group T), 0.3 ml/kg (group I), and 0.7 ml/kg (group C) of a 0.25% levobupivacaine solution with 1/200,000 adrenalin for the TAP block, II/IH block, and caudal block. The primary aim was to compare postoperative analgesic consumption within the first 24 hours after surgery. The secondary aim were to compare the mCHEOPS score, first analgesic requirement time, vital signs, and undesirable effects such as nausea and vomiting, which were recorded in the surgical ward at 1, 4, 8, 16, and 24 hours after surgery.Results:Ninety patients with American Society of Anesthesiology physical status class I-II were randomized into 3 groups (group I, group T, and group C). The total amount of analgesic consumption was significantly higher in Group I compared with Groups T and C (p=0.003). Pain scores at 1, 4, and 8 hours were significantly higher in Group I compared with the other 2 groups; however, pain scores in Group I at 16 hours were significantly higher only compared with Group C (p<0.05).Conclusion:Caudal and TAP blocks are more effective than II/IH nerve blocks in the early postoperative period.