Background : Previous studies have proven beneficial in labor analgesia to use subarachnoid sufentanil(alone or with adjuvant) on parturients in early first stage of labor. We designed this prospective study to evaluate analgesic efficacy and side effects of subarachnoid sufentanil plus bupivacaine in women with cervical dilatation of 7 cm greater. Methods : This was an open-label, nonrandomized trial of 32 parturients in late first stage labor who requested labor analgesia. After signing the consent form each patient received subarachnoid sufentanil (10 ${mu}g$) and bupivacaine (2.5 mg). Patients were asked to rate their verbal pain score (0-10 scale) before regional anesthesia and 5 minutes after subarachnoid injection, and every 20 minutes thereafter until delivery or request for additional analgesia. Blood pressure, pruritus, Bromage motor block score, mode of delivery and need for supplemental analgesics were recorded. Results : Thirty women were included in the study. Mean pain scores (mean${pm}$SD) were $8.7{pm}1.0$ pre-spinal, $0.7{pm}1.5$ 5 minutes post-injection, and remained less than 5 for 130 minutes after spinal injection. Of 30 patients, 24 had unassisted vaginal delivery, 4 instrumental vaginal delivery (vacuum), and 2 cesarean delivery. Of 28 patients who delivered vaginally, 19 did not require supplemental analgesics and had a delivery pain score of 5 or lower. Blood pressure decreased in three patients after spinal analgesia (p<0.05), which necessitated treatment. The Bromage motor block score was 0 in 26 patients and 1 in 4 patients. Pruritus was noted in 22 patients. Conclusion : Subarachnoid sufentanil-bupivacaine provides rapid analgesia for an effective duration of approximately 130 minutes in parturients in late first stage of labor.