The appearance of proteinuria in an insulin-dependent diabetic patient is an ominous sign. Proteinuria heralds the presence of diabetic nephropathy and early death, or chronic renal failure requiring dialysis or transplantation, in 50% of patients. The pathogenesis of diabetic nephropathy is unknown. Adequate insulin administration is the most important preventive measure. Hypertension, if present, should be aggressively treated to delay progression of renal disease. Good nutrition, prompt treatment of urinary tract infections, and caution in the use of radiocontrast agents are other important preventive measures. Hemodialysis, peritoneal dialysis, and transplantation are options for patients with end-stage renal disease. No matter which is selected, the patient may still have multiple amputations, blindness, congestive heart failure, infections, and uncontrolled glycemia. Advancements are being made, however, that promise a better future for insulin-dependent diabetics.