Objective: In a prospective study, clinical effects of intrathecal 0.5% hyperbaric bupivacaine 15 mg with fentanyl 25µg versus 0.5% hyperbaric bupivacaine 15 mg were compared in total 60 patients of ASA grade I and II undergoing lower limb surgeries. Methods: After receiving 500 ml lactated ringers solution without any premedication spinal anaesthesia was given in sitting position with 25 gauge quincke type spinal needle at L3-L4 space. Intrathecal 0.5% hyperbaric bupivacaine 15 mg with fentanyl 25µg or 0.5% hyperbaric bupivacaine 15 mg was given. Following factors were evaluated after the administration of spinal drug. Onset, maximum level and degree of sensory analgesia; Onset and degree of motor blockade, level of alertness and anxiety, hemodynamics, sensory and motor recovery, duration of effective analgesia and complications. Results: There was excellent intraoperative and early postoperative analgesia with addition of intrathecal fentanyl to bupivacaine as compared to giving intrathecal bupivacaine only. Sedation was an advantageous side effect inspite of pruritus and there was less nausea, vomiting and shivering with intrathecal fentanyl. Hemodynamic variables were unchanged with intrathecal fentanyl except respiratory rate which decreased upto 2 hours only. Conclusion: In patients with lower limb surgeries 25µg fentanyl along with 0.5% hyperbaric bupivacaine 15 mg is recommended inspite of mild pruritus with advantage of excellent intraoperative analgesia, sedation and prolonged postoperative analgesia.