Forty elderly patients (mean age 78.9 years) undergoing acute surgery for hip fracture were given at random either spinal analgesia with bupivacaine 0.75% or general anaesthesia with diazepam, fentanly and N2O/O2. Mental function was studied pre-operatively with an abbreviated mental test and 1 week and 3 months postoperatively in both groups. Mortality and number of complications was similar in the two groups, but a shorter time of ambulation was seen in the spinal group compared to the general anaesthetic group. No persistent impairment in mental function was found after acute hip surgery under spinal or general anaesthesia and the only advantage of regional technique was a shorter time of ambulation.