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. The aim of this study was to evaluate the onset and duration of sensory and motor block, hemodynamic effect, postoperative analgesia, and adverse effects of dexmedetomidine or fentanyl given intrathecally with hyperbaric 0.5% bupivacaine. Aim and Objective: To study the hemodynamic effects and assess the adverse effects of intrathecal dexmedetomidine and midazolam in lower limb and abdominal surgeries. Methodology: The Department of Anaesthesiology at Santosh Medical College & Hospital in Ghaziabad, Uttar Pradesh, conducted this prospective, randomised clinical study for a full year from May 2016 to May 2017. 60 patients underwent elective procedures on their lower limbs and abdomen. Patients must be between the ages of 18 and 60 in order to undergo surgery on the lower limbs and the abdomen. The patients were given ASA grades I and II. Result: The three groups' MAP means were examined. Group D baseline MAP was 92.60±6.524 mm Hg, group M was 93.25±8.187, and group C was 90.80 ±8.519 mm Hg. Conclusion: Intrathecal dexmedetomidine is associated with prolonged motor and sensory block, hemodynamic stability, and reduced demand for rescue analgesics in 24 h as compared to fentanyl.