A double catheter, single interspace combined spinal-epidural anaesthetic was performed in 12 ASA grade 3 patients. The technique failed in one patient in whom the intrathecal catheter could not be inserted satisfactorily. In another patient, the epidural catheter was accidentally placed intrathecally. The maximum height of the block obtained with hyperbaric lignocaine or bupivacaine was below T,, in all patients and there were no adverse cardiovascular changes. As opposed to a classical combined spinal-epidural block, this technique is most suitable for very debilitated patients. The advantages are the ability to titrate the intrathecal dose of the local anaesthetic to achieve the desired dermatomal level and to test the correct position of the epidural catheter before injecting drugs intrathecally.