Diabetic nephropathy: The kidney disease associated with long-standing diabetes. Diabetic nephropathy is also called Kimmelstiel-Wilson disease (or Kimmelstiel-Wilson syndrome) or intercapillary glomerulonephritis.

Diabetic nephropathy typically affects the network of tiny blood vessels (the microvasculature) in the glomerulus, a key structure in the kidney composed of capillary blood vessels. The glomerulus is critically necessary for the filtration of the blood. Features of diabetic nephropathy include the nephrotic syndrome with excessive filtration of protein into the urine (proteinuria), high blood pressure (hypertension), and progressively impaired kidney function. When it is severe, diabetic nephropathy leads to kidney failure, end-stage renal disease, and the need for chronic dialysis or a kidney transplant.

The name Kimmelstiel-Wilson disease is often used. It honors Paul Kimmelstiel (1900-70), a German-born pathologist in the US, and Clifford Wilson (1906-), an English physician.