Background: Caudal anaesthesia is used as pain control for many sub umbilical surgical procedures.
Objectives: This study intended to Estimate length of analgesia (1ry outcome) Track  haemodynamics and detect  side effects
Patients and methods: This prospective randomized double blind observational study was conducted on 60 healthy paediatric patients recruited from Qena university hospital, South Valley University, Qena, Egypt,  undergoing elective lower abdominal and pelvic surgeries were allocated to two groups according to mode of blocking agents and caudal region during the study duration from May 2019 to August 2020
Results: efficacy of ketamine bupivacaine versus nalbuphine bupivacaine to provide intraoperative and postoperative pain relief. The time to first analgesic administration was longer in the ketamine bupivacaine group about (8 hrs) than nalbuphine bupivacaine about (5.8 hrs).,
Conclusion: Caudal nalbuphine and caudal ketamine are safe in pediatric surgeries in the lower half of the body and effectively reducing postoperative pain with longer duration of analgesia in ketamine group than nalbuphine group with no obvious side effects in both groups.