
Background: Caudal epidural analgesia with bupivacaine is very popular in pediatric anesthesia for providing intra and post-operative analgesia. Several adjuvants have been used to prolong the action of bupivacaine. Objective: To compare the efficacy of Tramadol and Fentanyl in terms of quality and duration of analgesia they produce when added with bupivacaine by single shot caudal-epidural technique in children. Study design: Randomized Controlled Trial. Method: Sixty children, aged three to seven years, undergoing hypospadias surgery were prospectively randomized into two groups: 1. Caudal analgesia with 1 ml/kg of 0.25% bupivacaine with Tramadol 1mg/kg in Group A. 2. Caudal analgesia with 1 ml/kg of 0.25% bupivacaine with Fentanyl1 µg/kg as Group B. Post-operatively pain was assessed by Modified Objective Pain Score (MOPS). Result: The mean duration of analgesia was significantly longer in Group A(756.24±67.83) than the mean analgesic duration of Group B (464±31.79).The pain score assessed using Modified Objective Pain Score (MOPS).The children of group A has required less analgesic dose than the group B. Hemodynamics and level of sedation were similar in two groups. Post- operatively analgesia was supplemented with inj. Febrinil 8 mg/kg by intravenous route. Any adverse effects like respiratory depression, nausea, vomiting were recorded in all patients. Conclusion: For caudal block, Tramadol 1 mg/kg or Fentanyl 1 µg/kg significantly prolong the duration of analgesia and reduces the intra and post-operative analgesic requirements with preserved hemodynamic stability and lack of sedation, thus allowing single shot caudal anesthesia to be recommended for surgery lasting more than 150 minutes. So they may be the drug of choice to prolong duration of caudal anesthesia without respiratory depression.