Autopsies of all uraemic patients in Leningrad for three years, and materials of the City Nephrological Service have demonstrated that the structures of nephrological diseases in their early and terminal stages were different. Chronic glomerulonephritis has been noted in patients with normal renal function just as often as chronic pyelonephritis but the former prevails considerably among the causes of uraemia. The proportion of polycystic kidney disease, amyloidosis, and diabetic nephropathy increases in patients with chronic renal failure. Due to these changes and the difference in the death age of patients with various diseases the majority of patients suitable for treatment with long-term dialysis suffer from chronic glomerulonephritis and only 14.89-20.5% from chronic pyelonephritis.