Spinal anesthesia has been widely used for operations performed in the lower abdomen, inguinal regions, lower extremities, and perineum. When patient have aevere systemic disease and a full . stomach, spinal anesthesia is may be more safe than general aneethesia. Bradycardia and hypotension have been accepted to be the most common complications in cardio-vascular system during spinal anesthesia. The mechanisms are a decrease in total peripheral vascular resistance, a decrease in cardiac output or a combination of both. Accessory factors include bradycardia resulting from block of accelerator impulses to the heart or decrease in endogeneous release of norepinephrine from sympathetic nerve endings, thereby reducing myocardial contractility. We report 2 cases of sudden extreme bradycardia and hypotension in patients who had received spinal anestesia. Although the exact pathophysiology of this phenomenon is unknown, the etiology is probably vagal effect. Thus the patient who receives spinal anestbesia should be required constant monitoring and vigilance throughout all procedures.