OBJECTIVE A study to compare the efficacy between fentanyl and sufentanil combined with low concentration (0.0625%) of bupivacaine for epidural labor analgesia in laboring women METHODS Fifty full term parturients received an initial bolus dose of a 10 ml solution containing 0.125% bupivacaine. The patients were randomly divided into two: group F received 0.0625% bupivacaine with 2.5 mcg/ml fentanyl and group S received 0.0625% bupivacaine with 0.25 mcg/ml sufentanil. Verbal analogue pain scores, need of supplementary/rescue boluses dose of bupivacaine consumed, mode of delivery, maternal satisfaction, and neonatal Apgar scores were recorded. No significant difference was observed between both groups. RESULTS Both the groups provided equivalent labor analgesia and maternal satisfaction. The chances of cesarean delivery were also not increased in any group. No difference in the cephalad extent of sensory analgesia, motor block or neonatal Apgar score were observed. Although mean pain scores throughout the labor and delivery were similar in both groups, more patients in fentanyl group required supplementary boluses though not statistically significant. CONCLUSIONS We conclude that both 0.0625% bupivacaine-fentanyl (2.5 μg/ml) and 0.0625% bupivacaine-sufentanil (0.25 μg/ml) were equally effective by continuous epidural infusion in providing labor analgesia with hemodynamic stability achieving equivalent maternal satisfaction without serious maternal or fetal side effects. We found that sufentanil was 10 times more potent than fentanyl as an analgesic for continuous epidural labor analgesia.