Clinical signs of neuropathy, vibratory perception thresholds, nerve conduction velocities, and distal motor latencies were compared in 81 patients with chronic renal failure. During treatment with low protein diets (LPD), the vibratory thresholds correlated better with the clinical grading of the neuropathy than did the conduction velocities or the distal motor latencies, while during hemodialysis (HD), the situation was the reverse. The vibratory threshold on the foot was the single most useful test, since it correlated with the clinical grading of the neuropathy both during LPD and HD, and both between and within patients.