Any type of chronic renal disease is associated with functional deterioration of the kidney due to progressive glomerulosclerosis with interstitial fibrosis and tubular atrophy. This process is thought to be predominantly due either to glomerular hyperfiltration or mesangial overload with macromolecules. Antihypertensive therapy, particularly with ACE inhibitors, and protein restriction have been found to retard progressive glomerulosclerosis in animal experiments. There is no doubt that patients with renal disease benefit from antihypertensive therapy through both preservation of renal function and prevention of secondary organ damage due to hypertension. However, the value of protein restricted diets with or without supplements of essential amino acids or ketoacids is less clear. A patient treated with protein restriction is presented and the investigations necessary to monitor compliance, renal function and nutrition are discussed. Monthly to quarterly controls of renal function, blood pressure and mineral metabolism are suggested, particularly in the case of severe hypertension and of prophylactic treatment for renal osteodystrophy with phosphate binders and vitamin D metabolites. Finally, guidelines are provided for planning of renal replacement therapy by dialysis and renal transplantation in the individual patient.