Eighty-four patients with primary end stage renal disease (ESRD) of varying duration and severity were investigated by a single determination of facial nerve latency and determination of motor nerve conduction velocities of the peroneal, median, and ulnar nerves. Electrophysiologic evidence of motor neuropathy was found in 72 patients. In the facial nerve, conduction was abnormal in 82% of the patients; in the peroneal nerve it was abnormal in 68%; in the median nerve it was abnormal in 36%; and in the ulnar nerve it was abnormal in 22%. The facial nerve was the most sensitive indicator of uremic neuropathy of the 4 motor nerves studied. Information obtained from monitoring the facial nerve in patients with chronic renal failure will add significantly to the data used to identify uremic neuropathy. Combined studies of the facial, peroneal, and median nerves should identify most patients with uremic neuropathy.