Introduction: Spinal anaesthesia is a very popular and common regional anaesthesia technique for infra umbilical surgeries. However the short duration of action of local anaesthetic drugs used for spinal anesthesia results in early postoperative analgesic intervention. Intrathecal (I/T) administration of opioids with local anaesthetics improves quality and duration of the spinal blockade, and prolongs post-operative analgesia after surgery. Aims & objectives: To study the onset of sensory & motor block. To study and compare intra operative quality and duration of anaesthesia and level of spinal block. To study and compare perioperative hemodynamic effects by spinal block. To study the post operative analgesia. To study the occurrence of side effects and complications if any. Material and Methods: The present study is a randomized prospective comparative controlled study between age group 18–50 years of both sexes belonging to ASA grade I & II for elective infra umbilical surgeries. Written and Informed consent before participation in study will be taken from all patients. 90 patients will be divided into 3 groups (n = 30), will be schedule to undergo elective infra umbilical surgeries; Group 1: Bupivacaine heavy (0.5%) 3 ml + 0.5 ml NS Group 2: Bupivacaine (3 ml) + 0.5 ml (0.5 mg) Nalbuphine Group 3: Bupivacaine (3 ml) + 0.5 ml (0.5 mg) Butorphanol. Parameters like HR, SBP, DBP (hemodynamic variables), Respiratory rate, SpO2 will be monitor preoperatively &intraoperatively at 0, 5, 10, 15, 20 min and after that every 20 min till the end of surgery. Post operatively pain will be monitor at the end of surgery, then after every 1 hour till 1st 6 hours, then after every 6 hours till 24 hours. Sensory block level will be assess by pin prick test and motor block by Modified Bromage Scale will be use to assess the degree & duration of motor blockade. The intensity of pain will be assess by Visual analogue Scale (VAS) at the end of surgery then after every 1 hour till 1st 6 hours, then after every 6 hours till 24 hours. Patient will also be observed for any side effects and complications viz; hypotension, hypoxia, sedation, desaturation etc. These complications Sedation will be assessed by RAMSAY sedation score. Result & Conclusion: Statistical analysis was done by using SPSS. The difference in proportion was analyzed by one way ANOVA test and the inter group difference in means were analyzed by using post –hoc Tukey test. Significance level for tests was determined as p < 0.05. Onset of sensory & motor blockade remain insignificant (p > 0.05) whereas duration & quality of sensory & motor blockade and duration of analgesia remain significant (p < 0.05) in study groups. From our study we conclude that intrathecal inj. Bupivacaine combination with inj. Nalbuphine is better than inj. Bupivacaine combination with inj. Butorphanol in respect to the duration of sensory & motor blockade, quality of anaesthesia and duration of analgesia (requirement of rescue analgesia) without any significant increase in adverse effects, whereas sedation remains more with inj. Butorphanol as compare to inj. Nalbuphine.