The combination of sufentanil with bupivacaine plus adrenaline given extradurally for pain relief during labour was studied in a double-blind trial. One hundred and twenty patients were randomly divided into three groups and received a 10-ml extradural injection of sufentanil 15 micrograms + bupivacaine 12.5 mg + adrenaline 12.5 micrograms, sufentanil 7.5 micrograms + bupivacaine 12.5 mg + adrenaline 12.5 micrograms, or bupivacaine 12.5 mg + adrenaline 12.5 micrograms (control group). A second injection, which was given upon request, was identical to the first. Subsequently, patients received a further 10 ml of bupivacaine + adrenaline, if required. The addition of sufentanil significantly decreased the latency, and increased the duration, of the analgesia. Moreover, the quality of analgesia was better and less bupivacaine was required, resulting in less motor blockade at delivery. There were no differences between the three groups in regard to Apgar scores. The only side effect of sufentanil was pruritus.