In order to evaluate the degree and type of hearing loss in patients with chronic renal failure, 61 patients undergoing chronic hemodialysis were examined. Hearing threshold levels, adjusted for age and sex, demonstrated a significant high frequency deficit, which in some patients was noted early in the course of hemodialysis. Fluctuations in hearing were noted over single dialysis events but were transient and apparently independent of corresponding changes in Na, K, Ca, BUN, creatinine, glucose, mean blood pressure, and weight. Preliminary attempts to evaluate hyperlipidemia as a possible cause of hearing loss did not reveal any hearing deficit or gain as related to triglyceride or cholesterol levels. The data suggested other possible causes of observed auditory loss.