Major surgeries such as total hip arthroplasty are likely to be associated with high incidences of perioperative morbidity and mortality, which may be compounded by the increased risk of heavy bleeding. It has been reported that these complications may occur more commonly when general, rather than spinal anesthesia is used. This study was undertaken to investigate whether spinal anesthesia is clinically safer than general anesthesia undergoing total hip arthroplasty. Forty-one patients were classified randomly into 2 groups to compare the effects of spinal versus general anesthesia on blood pressure, pulse rate, amounts of blood loss and transfusion, and complications in total hip arthroplasty. In general anesthesia groups, systolic blood pressure significantly increased from the baseline of 125.6+/-14.4 mmHg to 137.2+/-12.7 mmHg at 10 minutes post-induction (p<0.05). Pulse rate also increased from the baseline of 75.2+/-1.6 beats/min to 90.3+/-8.0 beats/min at 10 minutes post- induction. In spinal anesthesia group, systolic blood pressure significantly decreased from the baseline of 121.5+/-11.5 mmHg to 113.4+/-15.8 mmHg at 10 minutes post-induction (p<0.05). Pulse rate also decreased from the baseline 78.6+/-11.9 beats/min to 74.2+/-5.2 beats/min at 10 minutes post-induction. After 10 minutes post-induction, systolic blood pressure and pulse rate became stable in both groups. The amount of intraoperative blood loss was less in spinal anesthesia group (510+/-140 ml) than in the g anesthesia group (720+/-150 ml). However, difference in the amount of blood transfused was not significant in the two groups. Postoperative hemoglobin values showed a marked decreases in both group. The complication rates were similar in both groups. It appears that blood loss during total bip arthroplasty is less in the spinal than general anesthesia group. However, other clinical variables investigated are not significantly different in the two groups.