Background: Spinal anesthesia produces hypotension more often in elderly patients than in younger patients due to decrease systemic vascular resistance mainly. Limiting the dose (and thus, extent of anesthetic spread) to the necessary dermatomes reduces the likelihood of side effects. The aim of the study was to compare hemodynamic effects of spinal anesthesia by using different bupivacaine concentrations in elderly cardiac patients undergoing TURP. Methods: This prospective randomized controlled double-blinded study was carried out on 60 male patients aged 65 years and above, American Society of Anesthesiologists (ASA) III, with IHD (history of MI, a history of a positive treadmill test result (ECG stress test), use of nitroglycerin, chronic stable angina for more than two months, or an ECG with abnormal Q waves), with ejection fraction (EF) 35%-50%, undergoing TURP with prostate from 100-150 gm by using bipolar resection technique and normal saline wash during surgical procedure. Patients were randomly allocated into two equal groups: Group I (Control group): received 2.5 ml bupivacaine 0.5% + 0.5 ml fentanyl (25 mcg). Group II: received 1.75ml bupivacaine 0.5% + 0.75 ml distilled water + 0.5 ml fentanyl (25 mcg). Results: Mean arterial blood pressure was significantly decreased in group I than group II at 6, 9, 12, 15 and 30 minutes. Heart rate and peripheral oxygen saturation were insignificantly different between both groups. Ischemia occurred in 3 (10%) patients in group I and no patients in group II & the difference between both groups was insignificant. Hypotension was found significantly higher in group I than group II (P = 0.021) while PONV, bradycardia, headache, backache and shivering were insignificantly different between both groups. TURP syndrome didn’t occur in any case of our study. Conclusions: Hyperbaric bupivacaine 8.75 mg injected at L4-L5 is sufficient to provide adequate sensory and motor block, while maintaining hemodynamic stability during TURP procedures.