The search for an ideal combination of agents for labor epidural anesthesia has become a focus of current research studies. This study was performed to determine if a combination of sufentanil with bupivacaine would show superior analgesia and fewer side effects when compared with an equipotent combination of fentanyl with bupivacaine in continuous labor epidurals. After the approval of the Human Investigations Committee and written consent from the subjects, 54 parturients were assigned to receive one of two epidural drug combinations in a randomized double-blind design. Group S received a bolus of 10 mL of 2 micrograms/mL of sufentanil in 0.125% bupivacaine followed by an infusion of 0.4 micrograms/mL of sufentanil in 0.125% bupivacaine. Group F received a bolus of 10 mL of 10 micrograms/mL of fentanyl in 0.125% bupivacaine followed by an infusion of 2 micrograms/mL of fentanyl in 0.125% bupivacaine. Subsequent doses of 5 mL of 0.125% bupivacaine plain were given for inadequate analgesia per parturient request. Instrumentation included a visual analogue scale (VAS) for pain measurement and rating scales for side effects. Before the initial bolus, a baseline pain score was obtained. Pain scores and side effects were assessed at 30 minutes, 60 minutes, and hourly until delivery. Maternal satisfaction and apgar scores were recorded after delivery. There were no statistically significant differences found in VAS scores or requirement for epidural top-up injections between the two groups. Demographics, side effects, apgar scores, and maternal satisfaction scores were also comparable. Both sufentanil and fentanyl with bupivacaine provide comparably safe and satisfactory analgesia for labor epidural anesthesia.