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Background and Aims Caudal epidural block (CEB) is widely used for perioperative analgesia in pediatric infra-umbilical surgeries.This study aimed to evaluate accuracy of landmark-guided CEB needle placement with ultrasound (US) and identify the most reliable sonographic indicators of successful placement. Ultrasound guidance (USG) can improve precision by visualizing anatomical markers like sacral canal dilatation and saline spread, but its effectiveness in confirming proper placement remains underexplored.The study focuses on assessing the first-pass success rate and identifying reliable USG signs for accurate CEB placement.Methods This prospective observational study was conducted at a tertiary care institute in central India after institutional ethical approval (IHEC-LOP/2020/PG/Jan/01; CTRI/2021/06/034146). Seventy ASA I–II children aged 1–12 years scheduled for elective infra-umbilical surgeries under general anesthesia were enrolled after informed consent. CEB was performed using anatomical landmark technique, and US was used post-insertion to assess needle placement. Saline spread, sacral canal dilatation, and the pumping sign were recorded in both transverse( figure 1a) and longitudinal(figure 1b) probe orientations. First-pass success and overall success were evaluated.Results A total of 70 pediatric patients were included. The first-pass success rate of landmark-guided caudal epidural needle placement was 62.8%, with an overall success rate of 69%. Clear palpation of anatomical landmarks significantly improved first-pass accuracy (p < 0.05). Ultrasound revealed that transverse view, especially sacral canal dilatation and pumping sign, was most reliable for confirming correct needle placement, showing high sensitivity. The longitudinal view had higher specificity but lower sensitivity. Saline spread was less predictive when used alone. Ultrasound significantly improved placement accuracy by enabling real-time assessment, particularly with transverse sonographic markers.Abstract OP38 Figure 1aTransverse ultrasound view of the sacral hiatus demonstrating needle placement for caudal epidural blockAbstract OP38 Figure 1blongitudinal ultrasound view of the sacral canal showing needle path and epidural space during caudal blockConclusions This study emphasizes the limitations of landmark-based pediatric caudal epidural blocks, even with experienced providers. Ultrasound, particularly transverse views identifying sacral canal dilatation and pumping sign, significantly enhances placement accuracy and safety, suggesting its routine use to reduce failure rates and improve outcomes.