Fourteen patients with chronic glomerulonephritis and with Alport's syndrome were treated. Haemodialysis was performed 2--3 times weekly. The duration of treatment was from 10 months to 9 years. Serum levels of electrolytes, urea and creatinine were determined, the neurological condition was examined and nerve conduction velocity was measured in the lower and upper extremities. The determinations were done before and after haemodialysis. Subclinical manifestations of polyneuropathy were demonstrated with reduced motor-nerve conduction velocity in the lower extremities. A direct effect of single haemodialysis was far from uniform: usually the conduction velocity increased after haemodialysis and in some cases it decreased. There was no correlation between the serum levels of electrolytes, urea and creatinine and motor-nerve conduction velocity.