Patients with renal failure often have wasting syndrome, owing both to poor dietary intake and to the rigors and consequences of the uremic syndrome. Dietary therapy aims to improve nutritional status and also to minimize uremic toxicity and the metabolic imbalances associated with failing kidney function. Excessive protein intake can increase uremic toxicity, but opinion is divided as to when protein intake should be restricted. Restriction rarely is necessary until the glomerular filtration rate (GFR) is below 25 ml/min. When the GFR is between 4 and 10 ml/min, a diet containing 35 (for women and very small men) to 40 gm of high-quality protein will maintain good nutrition and relative freedom from symptoms. With a GFR below 4 to 5 ml/min, maintenance dialysis should be instituted or a supplemental diet containing essential amino acids may be used. Most patients should receive calories in the amount of at least 35 kcal/kg of body weight per day. Supplements of folic acid, pyridoxine hydrochloride, ascorbic acid, and the water-soluble vitamins should be given. Sodium and water restriction may be necessary.