A battery of cardiovascular reflex tests were performed on 20 patients with chronic renal failure on intermittent haemodialysis, to assess occurrence of parasympathetic and sympathetic abnormalities. Using age-adjusted confidence limits, elderly uraemics showed more extensive parasympathetic and sympathetic dysfunction than middle-aged patients. The results suggest that the autonomic nervous system in the elderly is more susceptible to uraemic toxins than in the middle aged. This should lead to better preventive and therapeutic strategies for older uraemics.