BACKGROUND: Intrathecal fentanyl has been known to have rapid analgesic effect for the first stage of labor, but pruritus usually occurs, and respiratory depression can happen. The addition of bupivacaine during intrathecal analgesia has been known to have synergistic action with intrathecal opioids. We observed the efficacy of the intrathecal injection of morphine, fentanyl, and bupivacaine on labor parturients. METHODS: 20 laboring patients were studied. Each patients received morphine 0.2 mg, bupivacaine 2.5 mg, and fentanyl 10 microgram intrathecally. Analgesia was assessed using visual analogue scale (VAS) score as the time elapsed from the drug administration to the delivery. Side effects such as nausea, vomiting, pruritus, urinary retention, respiratory depression, and hypotension were evaluated. RESULTS: The onset of analgesia was rapid (within 5 minutes) and VAS scores were significantly lower than pre-treatment value for 5 hours. The incidence of nausea or vomiting was 55% (11/20). Pruritus occurred 50% (10/20). The occurrence of urinary retention was 35% (7/20). Hypotension occurred 10% (2/20). No patient developed post dural-puncture headache, respiratory depression, fetal bradycardia, or motor weakness. More than 90% of the patients in this study said that they were satisfied with this analgesic procedure. CONCLUSIONS: Intrathecal injection of morphine 0.2 mg, fentanyl 10 microgram, and bupivacaine 2.5 mg provided rapid and effective analgesia in labor patients.