Lower limb surgeries could be performed under local, neuroaxial and general anesthesia, but neuroaxial block is the preferred method. Spinal block has rapid onset, deep block, lower risk of infection and is cost effective. However, post-operative pain is an important problem as the used drugs have limited duration of effect; so the post-operative analgesic administration is necessary. Hence the present study was planned to evaluate the intrathecal Dexmedetomidine and Fentanyl as an adjuvant to isobaric Bupivacaine for lower limb orthopaedic surgery in patients from Bihar region. The present study was planned in Department of Anesthesia, Nalanda Medical College and Hospital, Patna, Bihar. Total 30 cases of the patients of lower limb orthopaedic surgeries were enrolled in the present study. The Group I patients received the 2.5 mL volume of 0.5% hyperbaric bupivacaine and 5 µg dexmedetomidine in 0.5 mL of normal saline intrathecal (Dexmedetomidine (100 µg/mL) was diluted in preservative-free normal saline). The Group II patients received 2.5 mL volume of 0.5% hyperbaric bupivacaine with 25 µg fentanyl intrathecal. Intrathecal injection was given over approximately 10–15 s. immediately after completion of the injection patients were made to lie supine. The data generated from the present study concludes that the dexmedetomidine appears to be an attractive alternative to fentanyl as an adjuvant to spinal bupivacaine in surgical procedures. It provides good quality of intraoperative analgesia, hemodynamically stable conditions, minimal side effects, and excellent quality of postoperative analgesia.