The present study aimed at clinical evalution of dexmedetomidine 10 microgm, as an adjuvant to heavy bupivacaine 0.5% (4 ml) in subarachnoid block in patients scheduled for lower abdominal surgeries. Total no. of patients included in the study are 66 who are admitted in orthopaedic ward for lower limb surgeries, who are of ASA grade I & II and age group between 18–60yrs. All the routine investigations of the patients were done and after complete PAC and preoperative preparations, patients were taken into O.T, all the standard monitoring applied and for subarachnoid block hyperbaric Bupivacaine 0.5% is a dose of 4ml (20mg) combined with or without Dexmedetomidine was administrated according to the assigned study group: 1.Group A– Inj. Bupivacaine– 20mg alone– control group 2.Group B– Inj. Bupivacaine– 20mg with Dexmedetomidine 10mcg–study group Data on onset & offset of sensory & motor block, degree of muscle relaxation, postoperative pain free period were recorded. Dermatome level of block, vitals & drug related complications were also noted. On the basis of observations, following conclusions are drawn: Rapid onset & increased duration of sensory block was seen in Grp B, Onset of motor block & post operative pain free period was prolonged in Grp. B. Sedation score was from 0–2 in study group.Other complications in study group were not significant.