Both continuous spinal anaesthesia and continuous epidural anaesthesia are supposed to provide adequate post-operative pain relief. The purpose of this randomized, prospective study was to compare the quality of analgesia, occurence of side effects and patient satisfaction between spinal and epidural administration of bupivacaine during the first post-operative 72 h. One hundred and two patients scheduled for hip arthroplasty were randomly assigned to one of two groups: Group 1 received continuous spinal anaesthesia for intra-operative and post-operative management, Group 2 received continuous epidural anaesthesia. Immediately after surgery, the continuous spinal anaesthesia-group received a 1-mL bolus (bupivacaine 0.25%), followed by a continuous infusion of 10 mL over 24 h. The continuous epidural anaesthesia-group received a 10-mL bolus (bupivacaine 0.25%), followed by 2mL h−1. The level of pain was gauged from a verbal rating score and from a visual analogue scale; the degree of motor blockade was recorded using the Bromage score. In the continuous spinal anaesthesia-group 90.2% reported complete analgesia on the verbal rating scale, but only 21.6% of the continous epidural anaesthesia-group did. The visual analogue scale scores given by the continuous spinal anaesthesia-group were significantly lower than those of the continuous epidural anaesthesia-group. The percentage of patients with a motor block was significantly higher in the continuous spinal anaesthesia-group on the day of surgery and at the first post-operative day. During the first 24 h,nausea and vomiting occured more often in the continuous epidural anaesthesia-group. The satisfaction was considered excellent in 92.2% of the continuous spinal anaesthesia-group and in 70.6% of the continuous epidural anaesthesia-group. It is concluded that continuous spinal anaesthesia and continuous epidural anaesthesia are effective and safe for post-operative pain relief after hip replacement. Compared with continuous epidural anaesthesia, continuous spinal anaesthesia provides faster onset of pain relief,ensures better analgesia and results in more satisfied patients.