Intrathecal injection of a small amount of morphine was used to provide obstetric analgesia in 20 primiparous women in labor. When the cervix was 3~4cm dilated approximately, 0.25mg or 0.5mg of morphine was injected intrathecally in each patient. In all parturients, labor pains were completery relieved after 10~60 min and analgesia lasted 8 to 15 hours. The vital signs of all parturients after intrathecal morphine injection were stable. The analgesia was well achieved but there was no alteration of motor power or pinprick sensation. The maternal side effects such as itching, nausea, vomiting, somnolence and urinary retention occured in a high proportion of parturients, but severity of these side effects were mild in most cases. Urinary retention was most severe side effect in our cases. All newborns were scored as having 8~10 on Apgar scores at 1 min after birth.