Five patients with malignant nephrosclerosis (MNSC) and severe renal failure (mean plasma creatinine 926 micromoles/L) were followed for 52 to 83 months. Blood pressure was controlled by a minoxidil-nadolol-diuretic combination. Combined renal length (CRL) on presentation was greater than 18 cm in four patients and 15.3 cm in one patient. Plasma creatinine values declined into the second year, and improved function persisted into the third and fourth years after presentation. The patient with least renal mass on presentation had evidence of declining renal function at 60 months. The data suggest that CRL and sustained blood pressure control are critical determinants of both short- and long-term recovery and preservation of self-sustaining renal function in patients with MNSC.