Abstract Background: During spine surgery, mechanical and thermal trauma can cause muscle ischemia and damage to nerves innervating the paraspinal muscles. Therefore, it is often characterized by severe and diffuse pain in the postoperative period, so adequate postoperative analgesia is essential to allow early mobilization, reducing the incidence of postoper-ative respiratory complications, and decrease the risk of chronic pain syndrome. Aim of Study: To investigate the effectiveness of a mixture of dexmedetomidine and bupivacaine versus bupivacaine alone for ESB for postoperative analgesia in spine surgery. Patients and Methods: The study was conducted at Neu-rosurgery operation Theater at Souad Kafafi University Hos-pital-Misr University of science and Technology (MUST). 70 Patients aged above 21 years, scheduled for spine surgery, 35 patients in each group equally. Results: Intra operative Fentanyl Consumption (µg/kg) there was significantly lower in Bupivacaine & Dexmedeto-midine group (p<0.003). Postoperative pain (VAS-10) among both study groups there weren't significantly lower in Bupi-vacaine & Dexmedetomidine group throughout follow-up time points, but the differences were statistically significant at hour 8, 12 and 24. Post-operative morphine consumption there was significantly lower in Bupivacaine& Dexmedeto-midine group. Time to first postoperative dose was significantly longer in Bupivacaine & Dexmedetomidine group. Post-operative complications related to morphine consumption (nausea, vomiting and pruritus) were less frequent in Bupi-vacaine& Dexmedetomidine group, but the differences were statistically significant only in nausea. Conclusion: The addition of dexmedetomidine to bupi-vacaine in US-guided Erector Spinae block during spine surgery reduce both intra operative fentanyl consumption and post operative morphine consumption, significantly prolong time to first postoperative morphine dose and reduces post-operative Nausea, vomiting (PONV) and pruritis owing to lowering the total opioid consumption compared with bupi- vacaine alone.