Background: Choice of anaesthesia for surgery below the umbilicus is Subarachnoid block with Bupivacaine traditionally. Dexmedetomidine is being used with Ropivacaine to avoid side effects of Bupivacaine. The objective of this study is to compare the groups (group 1- only Ropivacaine and group 2- Ropivacaine with Dexmedetomidine) with respect to duration of sensory block and motor block, sedation, and complications. Material and Methods: This is a prospective observational study and 30 patients in each group were included. Duration of sensory block and motor block, scale of sedation and complications were looked for. Patients with bradycardia, AV block, using beta blockers, calcium channel blockers or anti-arrhythmic and hepatic or renal dysfunction were excluded. Mean and standard deviation for continuous variables, frequencies and percentages for categorial variables were determined. Chi-Square test, Paired T test, Independent T test or Unpaired Test, and Wilcoxon Sum Rank Test were done. Results: Mean age and weight of the group-1 were 38.80±4.2years and 62.23±5.43 kg and that of group-2 were 39.67±5.9 years and 63.45±6.23 kg respectively. Mean duration of sensory and motor blockade of the group-1 were 189±18.2 minutes and 158±18.77 minutes respectively and that of group-2 were 230±19.7 minutes and 189±21.34 minutes respectively (p<0.001). Ramsay sedation scores in the group with only Ropivacaine was 1.7 ± 0.3 while in Dexmedetomidine group was 2.4±0.3 (p<0.001). 13 patients experienced hypotension, 5 were from only Ropivacaine group and 8 were from Dexmedetomidine group(p<0.001). 12 patients experienced bradycardia among which 4 were from only Ropivacaine group and 8 from Dexmedetomidine group(p<0.001). Conclusion: Intravenous dexmedetomidine in patients getting 0.75% isobaric ropivacaine for subarachnoid block, increases time to two dermatomal regression of sensory blockade, duration of sensory block, duration of motor block and provides good sedation.