It has recently been suggested that prolonged protein restriction preceding dialysis may induce protein malnutrition and thus confer a poor prognosis during dialysis. We examined the records of all patients who were prescribed a very low protein diet (0.3 g/kg ideal body weight) plus supplemental essential amino acids and/or ketoacids for 6 to 72 months (median 26 months) preceding renal replacement, numbering 43. Hypoalbuminemia immediately preceding dialysis was present in only two patients. Final serum albumin averaged 4.1 +/- 0.4 (SD) g/dl. Final transferrin was subnormal in eight patients, but had been subnormal in six of these, without attendant hypoalbuminemia, for one to four years. Mean final transferrin was 241 +/- 56 mg/dl. Final serum cholesterol was below 150 mg/dl in six subjects, all of whom had normal levels of albumin (mean 4.0 +/- 0.2 g/dl) and a normal mean value for transferrin (211 +/- 22 mg/dl). In five patients who exhibited subnormal albumin and transferrin and high cholesterol concentrations at the beginning of dietary therapy, albumin and transferrin levels rose to normal or nearly normal, and hypercholesterolemia receded during the ensuing four months. Thus this predialysis dietary regimen, rather than causing protein malnutrition, prevents it; when protein malnutrition is present, this regimen corrects it.