Intrathecal hyperbaric bupivacaine for orthopedic surgeries has faster onset but episodes of hypotension, nausea, vomiting is more than intrathecal isobaric ropivacaine. Maximum level of sensory block height is higher with intrathecal bupivacaine compared to ropivacaine in equipotent doses. To detect a significant difference in mean duration of sensory block between groups B (Bupivacaine with fentanyl) and group R (Ropivacaine with fentanyl) with α = 0.05 & power = 80% the minimum number of 40 cases was required in each group. Randomization was done using a random number table generated from computer software and divided into 2 groups of 40 each. The mean of mean blood pressure showed a significant and consistent fall from the baseline after the sub arachnoid block. This fall was seen in both the groups and was statistically highly significant but was clinically within normal physiological limits. Similarly, the difference in the mean of mean blood pressure between the groups were statistically highly significant but were clinically comparable