We evaluated the effect of 10 microgram of fentanyl added to bupivacaine on sensory and motor blockade, By using a double blinded study design, 90 patients undergoing general lower extremities, orthopedic and urologic surgery were randomized into two group : Group I, bupivacaine 7.5 mg and fentanyl 10 microgram; Group II, bupivacaine 12.5 mg only. The final volume of intrathecal injectate was adjusted to 2.5 mL with normal saline solution. Spinal anesthesia was administered with the 27-gauge Whitacre needle at the L2-3 interspace with the patient in the lateral position. Neural block was assessed by using pinprick and a modified Bromage scale. The degree of motor blockade and median level of the upper limit of the sensory blockade were similar in both groups. The efficacy of blockade in group II (93.33%) is higher than that of in group I (88.88%) but not statistically significant. The incidence of side effects was not significantly different between both groups except vomiting in group I (11.11%). We concluded that fentanyl 10 microgram with 7.5 mg of bupivacaine increased only the maximal sensory level but not the motor blockade. The low dosage of intrathecal bupivacaine with fentanyl is as good as the conventional use of bupivacaine alone.