Introduction: spinal anaesthesia is most commonly used technique for abdominal surgeries as it is very economical, easy to administer and has rapid onset of action.Adjuvants like Morphine, Fentanyl, Clonidine, Dexmedetomidine, Neostigmine, Tramadol etc. are used for gain better quality of anaesthesia.

Objectives: The study was aimed to compare intrathecal Dexmedetomidine and Fentanyl as adjuvant to hyperbaric Bupivacaine in term of; (a) evaluation of sensory and motor blocks in regard to, onset duration, and quality of spinal anaesthesia (b) duration of post–operative analgesia and requirement of rescue analgesia within 24 hr after surgery. (c) Perioperative haemodynamic stability (d) side effects and complication.

 Methods: All selected patients were randomly divided into two groups as follow: group F: patients were given hyperbaric Bupivacaine 15 mg (3.0 ml) with 25 mcg (0.5 ml) Fentanyl. Group D: patients were given hyperbaric Bupivacaine15 mg (3.0 ml) with 5 mcg (0.5 ml) Dexmedetomidine to make final volume 3.5 ml. we used 50mcg/ml and 50 mcg/0.5 ml concentration of Fentanyl and Dexmedetomidine respectively. Group F and Group D was then compared.

Results: Patients in Dexmedetomidine group had a significantly longer duration of motor and sensory block than patients in Fentanyl group. The mean time regression of motor block to reach Bromage 0 was 227.83+12.24 min in Dexmedetomidine group and 179.96+9.29min in Fentanyl group (p<0.05). Duration of analgesia was 279.33+ 10.14 min in Dexmedetomidine group and 172.90+6.78 min in Fentanyl group (p<0.005).

Side effects: No significant difference was observed among different groups for any of the side effects.Hypotension, bradycardia is more inDexmedetomidine group than Fentanyl group.

Conclusion: The duration of analgesia and motor block was more prolonged with Dexmedetomidinegroup than Fentanyl group along with significant decrease in heart rate.