Unlike acute renal failure with its sudden reversible failure of kidney function, chronic renal failure is slowly progressive. It most often results from any disease that causes gradual loss of kidney function. It can range from mild dysfunction to severe kidney failure. Progression may continue to end-stage renal disease. Chronic renal failure usually occurs over a number of years as the internal structures of the kidney are slowly damaged. In the early stages, there may be no symptoms. In fact, progression may be so gradual that symptoms do not occur until kidney function is less than one-tenth of normal.

Chronic renal failure and end stage renal disease (ESRD) affect more than 2 out of 1000 people in the United States. Diabetes and hypertension are the two commonest causes and account for approximately two thirds of the cases of chronic renal failure and ESRD. Other major causes include glomerulonephritis of any type (one of the most common causes), polycystic kidney disease, Alport syndrome, reflux nephropathy, obstructive uropathy, kidney stones and infection, and analgesic nephropathy.

Chronic renal failure results in the accumulation of fluid and waste products in the body, causing azotemia and uremia. Azotemia is the build-up of nitrogen waste products in the blood. It may occur without symptoms. Uremia is the state of ill health resulting from renal failure. Most body systems are affected by chronic renal failure. Fluid retention and uremia can cause many complications (see Complications).