Introduction: Lumbosacral transitional vertebra (LSTV) is a congenital spinal anomaly defined as either sacralization of lumbar segment or lumbarization of sacral segment of the spine. Inaccurate identification of LSTV may lead to wrong level disc surgery with resultant failed back syndrome. Aim: To analyse the incidence, age & sex distribution of LSTV in low back pain patients. To analyse the intraoperative measures to avoid wrong level surgery in LSTV patients. Materials & methods: This study was done prospectively in 244 cases admitted with lowback pain and underwent surgery for lumbar disc prolapse in a tertiary care hospital near Chennai. Pre op evaluation done to identify LSTV, intra op C–arm and correlation with pre op image to identify correct level for surgery. Post op image to confirm correct level surgery was done for all cases. Conclusion: The reliability of combined radiological methods (x ray LS spine with D12, MRI sagittal to count from c2, MRI axial to look for iliolumbar ligaments ) to identify LSTV is 100%. Intra operative image guidance with C arm and correlation with preop imaging will reduce the Surgical error to 0 %.