The dialysis patient is aware that his behavior evokes reciprocal and complicating responses from important people in his environment. These interactions are perceived and conducted by neurochemical mechanisms which may be impaired in the abnormal chemical environment imposed in renal failure. It is the behaviors we comprehend as indicators of disordered nervous mechanisms. Therefore, it is logical that neurophysiological and neurobehavioral phenomena should be measured quantitatively in order 1) to estimate objectively the patients' success in achieving the goal of maintenance dialysis treatment, 2) to assess the comparative adequacy of dialysis regimens and 3) to provide objective endpoint measures which are relevant to uremia for further investigations of the etiology and pathogenesis of these critically significant uremic manifestations. Our experimental results illustrate that: 1) measures of conduction velocity, distal latency and response amplitudes, as employed by us, were relatively insensitive in the patients and circumstances studied; 2) several neurophysiological measures, i.e., the spontaneous EEG, VER latency and, perhaps, photic stimulation, on the other hand, are highly correlated with the severity of renal failure; 3) behavioral measures of sustained attention and alertness (TMT), of short-term memory (ASTM) and of cognitive manipulation of symbols (AR) are also highly correlated with the severity of renal failure; 4) some measured abnormalities improve following dialysis, but not always to normal--three residual impairments may indicate dialysis in adequacy; 5) several of these measures can provide objective evidence for adequacy of dialysis and other clinical and treatment effects in patients with renal failure.