Spinal  anaesthesia  for  cesarean  section  is  the  most  preferred  technique. Addition  of opioids like fentanyl to low dose of  hyperbaric bupivacaine , augments the analgesic effect of local anaesthetics, provides better hemodynamic stability and good anaesthetic status. Hence this study was planned to assess the duration of post operative analgesia in two groups of parturients, one group receiving inj 0.5% hyperbaric bupivacaine 10mg (2ml) and another group receiving inj 0.5% bupivacaine 7.5mg (1.5ml) + inj fentanyl 25micrograms (0.5ml) = 2ml intrathecally. It was concluded that the total duration of analgesia was prolonged in the group receiving fentanyl with low dose of hyperbaric bupivacaine  with a mean of 219.23±17.95 minutes as compared to the group receiving only conventional dose of hyperbaric bupivacaine with a mean duration of 156.27±13.69 minutes.