Patients with prednisone-resistant nephrotic syndrome and biopsy-proven focal segmental glomerulosclerosis were treated with intravenous methylprednisone. After the first 2 weeks of therapy, the average urine protein excretion decreased from 247 to 96 mg/m2/h (p < 0.04). Two of the 7 patients have had long-term, nearly complete remissions. The other patients relapsed. One relapsing patient was retreated with methylprednisolone and is now in remission. Four relapsing patients were treated with alkylating agents, in combination with methylprednisolone. All of these patients entered complete or partial remissions. Methylprednisolone causes a significant decrease in the proteinuria of children with focal segmental glomerulosclerosis. In addition, although the follow-up period is relatively short, it would appear that methylprednisolone, often in conjunction with an alkylating agent, has significantly improved the clinical status of these patients.