Episiotomy, the most common surgical procedure performed in women, produces considerable pain in the postpartum period, and responds poorly to systemic analgesics. Few data are available on the use of regional analgesia for postepisiotomy pain. Obstetricians have used pudendal nerve block (PNB) during the second stage of labor as an alternative to epidural analgesia. The efficacy of PNB has been improved by using nerve stimulation for specific nerve identification. This randomized, double-blind, placebo-controlled study tests the hypothesis that unilateral nerve stimulator-guided PNB reduces postepisiotomy pain. Forty women 18 years or older with a singleton fetus (37–40 weeks) in a vertex position, who had a vaginal delivery with mediolateral episiotomy were randomized to receive PNB with 15 mL of either ropivacaine 7.5 mg/mL or saline. The women assessed their level of pain at rest (bed rest) or during activities (sitting or walking) within the first 48 hours postpartum using a visual analog scale (VAS) with 0 indicating no pain and 100 mm indicating the highest level of pain. Pudendal nerve stimulation was successful in all patients. At rest, significantly lower VAS pain scores were reported in the PNB group than those in the control group at 3, 6,12, 24, and 48 hours after delivery (P < 0.05). While sitting or walking, the PNB group had reduced pain scores in the first 24 hours (P < 0.05). Additional analgesia with niflumic acid suppositories [700 mg every 12 hours for breakthrough pain (VAS >30 mm) was required in 3 patients (15%) of the PNB group and in 17 (85%) of the saline controls (P < 0.001]. Unexpectedly, pain relief in the PNB group was maintained at 48 hours - a time well beyond the expected duration of action of ropivacaine (16–18 hours). No PNB-related maternal complications were reported in the 48 hours after delivery. The investigators concluded from these findings that unilateral PNB decreases pain significantly after mediolateral episiotomy with a substantial reduction in the need for supplemental analgesia.