Autonomic dysreflexia can be a life-threatening problem if not promptly recognized and treated. Since the most common cause is bladder distension it is essential that the urologist be familiar with this syndrome. Several patients with serious complications owing to autonomic dysreflexia, including 1 mortality, are presented. The complications of autonomic dysreflexia result from a sudden marked rise in blood pressure, which may be severe enough to rupture single or multiple cerebral blood vessels or lead to a considerable increase in intracranial pressure. The neurophysiology, clinical features and therapeutic measures are discussed.