The erector spinae plane block (ESPB) is an interfascial plane block, which appears to be increasing in popularity. Introduced in 2016, primarily to alleviate thoracic neuropathic pain, the indications for the block have been expanding since then.In pediatric surgery, caudal block is a low-cost, simple, and effective procedure for postoperative analgesia and as the only anaesthetic strategy . Caudal block is recommended for most surgical operations in the lower body, primarily below the umbilicus, including lower limb surgeries, inguinal hernia repair, urinary and digestive system surgery. Lower limb is supplied from nerve terminals arising from both sacral (sciatic L4-S3) and lumber (femoral (L2-L4) plexus. Erector spinae muscles overlay on the sacral lamina and continue over the transverse processes of lumbar vertebrae, thus a sacral ESP block performed with an adequate volume will spread in interfacial plane and through sacral foramina blocking both femoral and sciatic nerve, thus providing adequate analgesia for paediatric lower limb surgeries. Caudal block has been successfully used as a part of multimodal analgesic regime in surgeries in paediatric patients. There is a lack of comprehensive research on Sacral erector spinae block in paediatric patients. Effectiveness of sacral ESPB determined by our study will add to the existing body of scientific literature supporting its use as analgesic technique in current practice.No randomised controlled trial has been conducted till date comparing sacral ESPB block to caudal block in paediatric patients. We expect that sacral ESP block will provide analgesia noninferior to caudal block in paediatric patients undergoing lower limb surgeries.