The insertion of the epidural catheter at the thoracic spine is technically more difficult and can cause neurological complications. The ultrasound prepuncture knowledge of the distance from the skin to the extradural space and a preview of the spinal anatomy may facilitate the procedure. Hence the aim of our study was to evaluate the accuracy of ultrasound in prediction of the depth for thoracic epidural insertion using paramedian approach. Aims and Objectives: To compare the depth of thoracic epidural space as measured by US compared to the actual depth of space by loss of resistance. Material Method: Thirty four patients, age  20 years undergoing any major surgery, requiring thoracic epidural for intraoperative and postoperative pain relief belonging to ASA 1-4 status were selected. The approval of research ethical committee of the institution was obtained. The written informed consent of patients were taken after explaining the procedure and the aim of the study in detail. The thoracic spine of these patients were scanned preoperatively with ultrasound in sitting position. The probe was placed vertically in the paramedian plane and the skin epidural depth was noted. After infiltrating the skin with 3 ml of 2% lignocaine, puncture was done. The actual depth of the space by loss of resistance was noted.The analysis of the data was done using paired ‘t test’, pearson correlation co-efficient and Bland- Altman analysis. Result: Both techniques differ in their measurements. Conclusion: Pre-puncture ultrasonography does not provide accurate assessment of depth of thoracic epidural space.