To demonstrate autonomic nervous system (ANS) disturbances in patients on chronic intermittent hemodialysis, simple noninvasive tests were used. These included the Valsalva maneuver ratio, measurement of the changes in blood pressure and pulse rate following standing up from the supine position, the finger-immersion test and calculating the R-R interval ratio of the 30th to the 15th beat on the ECG following standing. In all patients, compared with normal volunteers, some ANS disturbances were present, as evidenced by at least 3 positive tests of the 5 described. The Valsalva maneuver ratio was positive in only 58% of the cases, possibly because it is a less sensitive test than the others.