Subarachnoid block is the most widely used regional anaesthetic procedure for lower abdominal and lower limb surgery including lower segment caesarean section (LSCS). It provide rapid onset, consistent sensory and motor blockade with adequate muscle relaxation and for all types of surgery below the level of umbilicus. Regional anaesthesia is safer than general anaesthesia and having advantage of the parturient being awake during the birth process. Intrathecal local anaesthetics (LA) alone are not enough for effective postoperative analgesia and higher dose of LA are also associated with haemodynamic instability, which can lead to unfavourable maternal and foetal outcome. So far, many adjuvants have been used to augment the analgesia produced by intrathecal LA and to reduce their adverse effects. It has been well documented that the combination of fentanyl and LA administered intrathecally has synergistic analgesic effects. Fentanyl is a lipophilic j-receptor opioid agonist. Intrathecally, fentanyl exerts its effect by combining with opioid receptors in the dorsal horn of spinal cord and may have a supra spinal spread and action.Hyperbaric bupivacaine (0.5%), an amide-type of local anaesthetic, has been the gold standard for intrathecal use in spinal anaesthesia for many years but also has been associated with severe hypotension, delayed recovery of motor block, and cardiotoxicity when used in large concentration or when accidentally administered intravascularly. The introduction of ropivacaine has a better margin of safety for local anaesthetic systemic toxicity. Various studies have evaluated the effectiveness of these newer drugs for spinal anaesthesia using hyperbaric and isobaric solutions with a reliable rate of success. The study includes 140 pregnant patients aged, ASA grade I, and II scheduled for surgeries under subarachnoid block enrolled in this study and allocated into two groups of 70 patients each.  After shifted to the operating room, standard ASA monitoring was attached.  Group RF-  received intrathecally 0.5% Isobaric Ropivacaine (2.0 ml) +25mcg(0.5ml) fentanyl Group R- received intrathecally 0.5% Isobaric Ropivacaine (2.0 ml)+ 0.5ml NS 0.9Parameters noted were Hemodynamic parameters were recorded,immediately after administration of intrathecal drugs, 1 min, 3 min, 5 min, 10 min, 15 min, 30 min, 60 min, 90 min and 120 min after administration of intrathecal drugpost-operatively 15 min, 1hr and  2 hr. Time of onset, time to achieve maximum level and duration of sensory block noted &Time of onset and duration of motor block notedPostoperative pain was assessed by the VAS  scale and total analgesic requirement in the first 24 hours in two groups.Rescue Analgesia IV Diclofeneac 75mg IV SoS.