Introduction Attempts to evaluate the effects of uremia on the nervous system must separate those aspects secondary to the uremia from those attributable to the underlying disorder. Many diseases which affect the kidneys also directly affect the nervous system. In an attempt to distinguish the effects of uremia on the nervous system, a series of patients with acute uremia was studied. Cases of lupus erythematosus, sclerodema, polyarteritis nodosa, multiple myeloma, polycystic disease, and severe hypertension with renal involvement were excluded from consideration. Included in the category of acute renal failure were all cases in which there was no evidence of renal disease antedating the present illness and in which an acute insult could be postulated. Thirteen consecutive patients with acute anuria were seen in neurological consultation after admission to the Peter Bent Brigham Hospital. They were examined daily until discharged or until death. Specific attention was directed to the mental