Optimal dietary protein intake for adults with the nephrotic syndrome has not yet been established; very-low protein diets are believed to be contraindicated. Protein restriction has been known since 1985 to reduce proteinuria, and according to one preliminary report, to lead to an increase in serum albumin concentration. However, severely protein-restricted diets have rarely been tried in the nephrotic syndrome, probably for fear of aggravating hypoalbuminemia. This fear seem unfounded, and our preliminary observations in hypoalbuminemic subjects with chronic renal failure and substantial proteinuria indicate that rather than falling, serum albumin levels tend to rise when a very low protein diet, supplemented by essential amino acids, is administered to such subjects. The purpose of this project is, therefore, to determine whether a supplemented very low protein diet is beneficial in the nephrotic syndrome, and to ascertain which patients can be expected to benefit.