Objective:Caudal epidural analgesia has become very common analgesic technique in paediatric surgery.Adding tramadol to bupivacaine for caudal injection prolongs duration of analgesia with minimal side effects.The aim of the study was to investigate the different effects of caudal bupivacaine versus bupivacaine with thamadol for postoperative analgesia in paediatric cancer patients.Methods:A prospective randomized controlled trial was conducted over 40 paediatric cancer patients who were recruited from Children Cancer Hospital of Egypt(57357 Hospital).Patients were randomized into 2 groups:bupivacaine group(group B,20 patients) to receive single shot caudal block of 1 mL/kg 0.1875% bupivacaine;tramadol group(group T,20 patients) prepared as group B with the addition of 1 mg/kg caudal tramadol.Results:The mean duration of analgesia was significantly longer among group T than group B [(24 ± 13.7) hours versus(7 ± 3.7) hours respectively with P = 0.001].Group T showed a significantly lower mean FLACC score than group B(2.2 ± 0.9 versus 3.6 ± 0.6 with P = 0.002).The difference in FLACC score was comparable on arrival,and after 2 and 4 hours.At 8 and 12 hours the group B recorded significantly higher scores(P = 0.002 and 0.0001 respectively).There were no significant differences between the groups as regards sedation score [the median in both groups was 1(0-1) with P value = o.8].No one developed facial flush or pruritis.Conclusion:Caudal injection of low dose tramadol 1 mg/kg with bupivacaine 0.1875% is proved to be effective,long standing technique for postoperative analgesia in major paediatric cancer surgery and almost devoid of side effect. Objective: Caudal epidural analgesia has become very common analgesic technique in pediatric surgery. Adding tramadol to bupivacaine for caudal injection prolongs duration of analgesia with minimal side effects. AIM The study was to investigate the different effects of caudal bupivacaine versus bupivacaine with thamadol for postoperative analgesia in pediatric cancer patients. Methods: A prospective randomized controlled trial was conducted over 40 pediatric cancer patients who were recruited from Children Cancer Hospital of Egypt (57357 Hospital). Patients were randomized into 2 groups: bupivacaine group (group B, 20 patients ) to receive single shot caudal block of 1 mL / kg 0.1875% bupivacaine; tramadol group (group T, 20 patients) prepared as group B with the addition of 1 mg / kg caudal tramadol. Results: The mean duration of analgesia was significantly longer among group T than group B [(24 ± 13.7) hours versus (7 ± 3.7) hours respectively with P = 0.001] .Group T showed a significantly lo wer mean FLACC score than group B (2.2 ± 0.9 versus 3.6 ± 0.6 with P = 0.002). The difference in FLACC score was comparable on arrival, and after 2 and 4 hours. At 8 and 12 hours the group B recorded significantly higher scores (P = 0.002 and 0.0001 respectively) .There was no significant differences between the groups as regards sedation score [the median in both groups was 1 (0-1) with P value = o.8] .No developeddaral flush or pruritis .Conclusion: Caudal injection of low dose tramadol 1 mg / kg with bupivacaine 0.1875% is proved to be effective, long standing technique for postoperative analgesia in major pediatric cancer surgery and almost devoid of side effects.