One hundred and fifty patients who presented for transurethral prostatectomy were randomly allocated to one of three groups for the purpose of anaesthesia. Group A received spinal intradural analgesia, Group B general anaesthesia with spontaneous ventilation and Group C general anaesthesia with controlled ventilation. The comparability of the three groups was established. There were no significant differences in the corrected blood loss, postoperative morbidity or mortality in the three groups. Dysrhythmias were significantly higher in Group B. The results support the conclusion that the methods of choice for anaesthesia for transurethral prostatectomy are spinal analgesia or general anaesthesia using muscle relaxants and controlled ventilation. The final decision is a matter of personal preference.