We conducted this prospective, randomized study to compare the analgesic effect of femoral nerve block and IV fentanyl administration when given to facilitate the sitting position for spinal anesthesia in patients under for femoral shaft fracture. Five minutes going surgery before the placement of spinal block, group FEM patients (n = 10) received a femoral nerve block with lidocaine 1.5% 15 mL, and group IVA patients (n = 10) received IV fentanyl 3 mug/kg. Visual analog scale values during positioning (median and range) were lower in group FEM: 0.5 (0-1) versus 3 (2-6) (P < 0.001). Time to perform spinal anesthesia (mean +/- so) was shorter in group FEM: 1.8 +/- 0.7 min versus 3.0 +/- 1.1 min (P < 0.05). Quality of patient positioning for spinal anesthesia (0 = not satisfactory, 1 = satisfactory, 2 = good, and 3 = optimal) (median and range) was higher in group FEM: 3 (2-3) versus 1.5 (1-3) (P < 0.005). Patient acceptance was less in group IVA (P < 0.05). In one group IVA patient, an oxygen saturation <90% was recorded during the procedure. We conclude that femoral nerve block is more advantageous than IV administration of fentanyl to facilitate the sitting position for spinal anesthesia in patients undergoing surgery for femoral shaft fractures.