Bupivacaine, 0.125 per cent, with epinephrine, 1:800,000, was administered to 3,000 women in labor. Administration was in the lumbar epidural space for the purpose of achieving satisfactory analgesia with minimal or no motor paralysis. The usual initial dose of 12.5 mg (mean 13 +/- 2 SD) resulted in good sensory analgesia in 83 per cent of the patients and lasted for about and hour (mean 58 +/- 16 min). The mean total dose used for labor and delivery was 55 +/- 20 mg and the mean dose per hour 23 +/- 13 mg. Satisfactory analgesia for labor and delivery was obtained in 92 per cent of the patients, and in 66 per cent there was no discernible motor blockade. In the 3,000 patients, there was no adverse reaction to bupivacaine or epinephrine. No patient had a total spinal block or neurologic sequelae, and no neonatal depression could be attributed to the anesthetic.