The Coronary Artery Bypass Grafting (CABG) is associated with different morbidity and mortality. One of the morbidity associated with CABG are the hemodynamic changes during surgery which has become a major concern for professionals. One of the reasons for this morbidity is lack of adequate pain control and the use of opioids as part of a balanced anesthetic technique will lead to hemodynamic stability. Many experts suggest the association of general anesthesia with spinal anesthesia for hemodynamic stability. The aim of this study was to evaluate the effect of spinal anesthesia on patients' hemodynamic in coronary artery bypass surgery. This study was a randomized clinical trial in Ahwaz Golestan Hospital. 60 patients of 40 - 75 years old and ASA Class II and III who had a history of drug abuse were divided into two groups of general anesthesia and general anesthesia plus spinal anesthesia. During operation, levels of each patient's medications and hemodynamics parameters were recorded and at the end were calculated for each patient and used as comparison baseline The results obtained of this study show there were significant difference between two groups for the mean heart rate (p = 0.001), mean blood pressure (p = 0.003) and mean arterial pressure (p = 0.001). In this present study, the group receiving intrathecal morphine in comparison with the control group in hemodynamic conditions were more stable and the intrathecal morphine association with general anesthesia more dramatically lead to improve the mean heart rate, mean blood pressure and mean arterial pressure during sternotomy that of course this effect can be less observed when removing the pump.