Randomized, parallel-group, assessor-blinded clinical trial at Tanta University Hospitals comparing ultrasound-guided sacral erector spinae plane block (sESPB) versus ultrasound-guided caudal epidural block for postoperative analgesia in male children (1-5 years) undergoing hypospadias repair. Seventy participants will be randomized 1:1 to receive sESPB or caudal block with 0.25% bupivacaine (0.5-1 mL/kg; maximum 20 mL) after induction of general anesthesia. The primary outcome is pain over the first 24 hours, assessed using the FLACC scale at prespecified time points. Secondary outcomes include total opioid consumption, time to first rescue analgesia, postoperative nausea and vomiting, parent/guardian satisfaction, hemodynamic trends, and predefined adverse effects (e.g., motor weakness, urinary retention, respiratory depression, hematoma, infection at injection site). Perioperative care is standardized; rescue pethidine is administered when FLACC ≥4. The trial evaluates whether sESPB provides superior or comparable analgesia with fewer adverse effects than caudal block.