Inadvertent subarachnoid administration of epidural solution is a well-recognised, rare, but potentially life-threatening complication of obstetric analgesia. The recent introduction of combination low-dose bupivacaine and lipophilic opioid for epidural analgesia during labour creates the potential for both unintentional spinal anaesthesia and severe opioid-induced respiratory depression, should this complication occur. This case report describes the unrecognised subarachnoid injection of 0.125% bupivacaine with fentanyl 100 mcg, and a subsequent 'total spinal' after a second larger bolus dose of bupivacaine alone, in an obstetric patient having epidural analgesia in labour. CASE REPORT A 20-year-old, 84 kg primiparous woman was induced for post-maturity. Following two doses of intramuscular pethidine 100 mg, which did not provide adequate analgesia, she requested epidural analgesia. Cervical dilatation at this time was 3 cm. The anaesthetic registrar experienced considerable difficulty in siting an epidural catheter, making several attempts with the woman positioned both lateral and sitting. Eventually the epidural space was identified at a depth of 5 cm in the L2-3 interspace and a 16-gauge three side-holed catheter inserted 4 cm into the epidural space. After negative aspiration, a bolus dose of 12.5 mg of bupivacaine (0.125% plain bupivacaine 10 ml) combined with fentanyl 100 mcg, was administered. Rapid pain relief was obtained and