Background: The undertaking of complex and major surgical procedures on frail elderly patients with multiple disorders has always been and still remains a controversial and enigmatic issue. At the same time, in an increasingly ageing society, the need for such procedures will extend and the patients will expect a more favorable outcome. Surgery in old age will, therefore, pose an ongoing challenge.

Objectives: The aim of the study is comparative evaluation of bupivacaine plain versus bupivacaine with fentanyl in spinal anaesthesia in geriatric patients.

Methodology: This prospective study includes 60 patients of age 65 year or more than 65 year undergoing hip replacement. The study population was randomly allocated to two groups; Group A(n=30) - 15mg of 0.5% bupivacaine & Group B(n=30) - 10mg of 0.5% bupivacaine and 25μg of fentanyl.

Result: Systolic B.P. decreased in both the groups, maximum fall occurred at 15 to 20 min in both the groups: decreases were more severe in group A than in group B,(P<0.O5).heart rates were better maintained in group B than in group A. thus group B showed better hemodynamic stability. Group b had lesser duration of motor blockage without significantly compromising the duration of sensory block or the operative conditions. None of the patients required intraoperative anesthetic supplementation. 8 patients in group B had pruritus while none of the patients developed respiratory depression.

Conclusion: Spinal anesthesia for elderly patients undergoing lower limb surgeries with 2cc bupivacaine 0.5% and 25 μg fentanyl is a safer and better option, both in terms of maintaining hemodynamic stability and lower incidence of complications without compromising the surgical conditions.