Aims: The aim of the study is to compare the anaesthetic efficacy of intrathecal hyperbaric 0.5% Bupivacaine with 25mcg Fentanyl and intrathecal hyperbaric 0.5% Bupivacaine with 60mcg Buprenorphine for lower abdominal and lower limb surgeries Materials and methods: The present study was undertaken in Sixty patients (of either sex belonging to ASA I and II physical status) posted for elective lower abdominal and lower limb surgeries (under Spinal Anesthesia) were selected and were randomly allocated into two groups; Buprenorphine (Group B), and Fentanyl (Group F). Results: The demographic profile with regard to age ,gender, ASA grading, average duration of surgery were comparable in all the groups. The onset of block , mean time for onset of motor blockade,mean time for sensory regression, mean time for regression to bromage ‘1’ , mean duration of analgesia was the difference between the groups was statistically significant.Intraoperative heart rates were comparable among the two groups (p<0.005). isolated incidents of Bradycardia were noticed – but were neither statistically significant nor clinically significant. There was gradual fall in the SBP and DBP towards 30 minutes into surgery followed by a stable state .Both the groups were comparable (p>0.05) with regard to their MAP, although hypotension was noticed in both the categories of patients.All the adverse events were mild in nature which required no intervention. No episodes of respirat