Caudal epidural anesthesia has become widely accepted as a means of providing postoperative pain relief and mtraoperative supplementation to general anesthesia for children. Caudal anesthesia was given to 63 infants and children under 15 years of age, who received lower abdominal surgery. After thiopental sodium 4-5 mg/kg IV and 1-2Vo1% halothane inhalation, caudal block was performed in the lateral position. Halothane was stopped immediately after caudal block and only 50% NO in oxygen was inhaled through the mask during operation. The patients were randomly divided into four groups: Group 1; 0.33% bupivacaine 0.7 ml/kg, Group 11; 0.33% bupivacaine 1.0 ml/kg, Group III; fentanyl 1 ug/kg combined with 0.33% bupivacaine 1.0 ml/kg, Group IV; 1.5% lidocaine 1.0 ml/kg. The time of onset, duration of analgesia, side effects during and after operation, intial voiding time, and use of analgesics in the ward were observed. The results were as follows: 1) Caudal block was successful at the 1st attempt in most cases. 2) During operation, supplementation of other inhalational anesthesies were need. 3) In all groups, surgical anesthesia could be obtained within 10 minutes. 4) Intraoperative adverse effects were not detected except for minimal movements on skin incision and spermatic cord traction in 12 cases and vomiting in 2 cases. 5) Postoperative analgetic effects were good in all groups, especially in fentanyl group. 6) In most cases, patients ean void within 6 hours without urinary catheterization. 7) Postoperative analgesics were not needed and patients parent's were highly satisfied with caudal anesthesia in all cases. From the above results, it was suggested that caudal anesthesia with 0.33% bupivacaine or 1.5% lidocaine without potent inhalational anesthetics was satisfactory for lawer abdominal surgery and l ug/kg of fentanyl had some benefits in postoperative analgesia in children.