In 9 patients undergoing chronic hemodialysis for 2–10 years and suffering from encephalopathy (dialysis dementia) and peripheral neuropathy, 10 mg of biotin was given daily in three doses for 1–4 years. Within 3 months there was a marked improvement in all patients in respect to disorientation, speech disorders, memory failure, myoclonic jerks, flapping tremor, restless legs, paresthesia and difficulties in walking. It is recommended to start giving biotin regularly in any patient with advanced renal failure before severe neural or muscular lesions become manifest. The correlation of biotin with uremic neurologic disorders and the possible mechanism of its therapeutic action are discus