Common neurological conditions seen in renal failure are presented to serve as a background for the presentation of recent experimental work on animal models. Uremic encephalopathies are associated with mental changes, disturbances of consciousness, seizure states, asterixis, myoclonus, and definite electroencephalographic abnormalities. An attempt is made to relate these to the usual biochemical concomitants of the patients. No single or simple explanation at present appears to be adequate to explain the phenomena seen. The effect of dialysis and transplantation on these syndromes as well as neurological problems specifically related to these therapeutic techniques is discussed. Infections are particularly prone to develop, often with unusual organisms. A few patients with unusual central nervous system tumors possibly related to immunosuppressant therapy have been reported.