A case of bilateral compartment syndrome after prolonged Lloyd-Davies lithotomy position is described. The diagnosis was made early, despite effective extradural bupivacaine-fentanyl analgesia. The aetiology, diagnosis, pathology and treatment of compartment syndrome are described. Complications of the syndrome may be life-threatening and permanently disabling. The anaesthetist should be aware of the potential complications of the operative positions of the unconscious patient.