Organ changes during the aging are one of the signifi cant events in old patients. rthopedic surgeries are common operations in these patients that accompany with hemodynamic changes as blood pressure decrease, heart rate, and respiratory rate change. On the other hand, pain management of the ancient patients due to negative consequences as tachycardia, blood pressure increase, and myocardial ischemia is vital. Various types of opioid analgesics have been used in order to pain control in these patients. We decided to conduct the present study in order to compare the hemodynamic changes of the old patients who undergo lower limbs orthopedic surgeries by applying subarachnoid bupivacaine and meperidine (pethidine).