Background: Various adjuvants have been used with local anesthetics in spinal anesthesia to avoid intraoperative visceral and somatic pain and to provide prolonged postoperative analgesia. Dexmedetomidine, the new highly selective α2-agonist drug, is now being used as a neuraxial adjuvant. Aim: to compare a combination of isobaric Levobupivacaine with fentanyl and dexmedetomidine for the characteristics of spinal blockade with respect to onset, duration and hemodynamic parameters and side effect. Material and methods: This was a prospective, randomized, and double blinded clinical comparative study conducted in the Department of Anaesthesiology, Netaji Subhas Medical College and Hospital ,Amhara, Bihta, Patna, India for 8 months. The study population consisted of 180 adult patients who were classified as American Society of Anaesthesiologists (ASA) physical status I or II, undergoing elective lower limb orthopaedic surgery under spinal anesthesia. The study participants were randomly divided into three groups. Group A: 0.5% Levobupivacaine Isobaric 2.5ml+ 0.5ml normal saline (total volume is upto 3.0 ml). Group F: 0.5% Levobupivacaine Isobaric 2.5ml + 25mug fentanyl (test solution will diluted with normal saline to total volume of 3.0ml). Group D: 0.5% Levobupivacaine isobaric 2.5ml +5 mcg dexmedetomidine (test solution will diluted with normal saline to total volume of 3.0 ml. Result: The mean time for onset of sensory block was 10.74 ±4.11 min in the saline group and 8.56±2.89 min in the dexmedetomidine group and 2.18±1.32 min in the fentanyl group. The mean time taken to achieve maximum sensory block in group A was 15.78±4.93 min, in group D was 13.36±3.62 min and in group F it was 5.42±1.87 min so maximum sensory block was achieved earlier in group. Peak level of sensory block attained in the fentanyl group was T4 and the peak level of sensory block in dexmedetomidine group was T6 and in the saline group peak level was T8. So the highest sensory block was attained in the fentanyl group. Conclusion: Dexmedetomidine group has longer onset of and duration of sensory block and effective postoperative analgesia and fewer side effects as compared to fentanyl group.