Spinal Anesthesia employing 0.5% plain bupivacaine was administered to 40 patients scheduled for lower limb or perineum surgery at Kyungpook National University Hospital. Two different volumes(3 and 4ml) and 2 different injection sites(lumbar interspaces L2/3 and L3/4) were used and their effects were compared. The patients were divided into four groups of 10: group A received 3ml of bupivacaine at L3/4, group B 3ml at L2/3, group C 4ml at L3/4 and group D 4ml at L2/3. The results were as follows: No significant difference were found between the 4 groups of patients in relation to age, height weight and length of surgery. The time for maximal sensory spread was 18.0±7.15 and 18.5±7.84 minutes in group B and C (p<0.05) and 20.0±7.84 minutes in group D (p<0.01) which showed a significant increase compared with 11.0±5.6 minutes in group A. Significant differences(p<0.05) in maximal sensory spread levels were observed between group A, B(T9) and group C, D(T7). No significant differences were found among the four groups in relation to the time of maximal motor blockade. Complete motor block was observed in all groups 20 minutes after spinal injection. Changes in blood pressure and pulse rate showed a significant(p<0.05) decrease in 10~15 minutes, and a very significant(p<0.01) decrease 20~30 minutes after spinal injection. Four patients experienced hypotension or bradycardia and two patients developed nauses or vomiting, but none of the patients developed a postspinal headache or micturition difficulty.