Sixty-five children with steroid-resistant idiopathic nephrosis were treated with cyclosporine, 150 to 200 mg/m2, in combination with prednisone, 30 mg/m2, daily for 1 month and on alternate days for 5 months. Renal biopsy had shown minimal change disease in 45 children and focal segmental glomerular sclerosis in 20. Twenty-seven patients achieved complete remission. At latest examination, 14 to 60 months after initiation of the treatment (mean, 38 months), 17 patients were in complete remission, 8 had had a relapse but had become steroid sensitive, and 2 had a nephrotic syndrome. Four children responded partially to the treatment. At latest examination, 28 to 58 months after initiation of the treatment, 1 was in complete remission, 1 was in partial remission, 1 had a nephrotic syndrome, and 1 had end-stage renal failure. Thirty-four children did not respond to the combined treatment. At latest examination, 12 to 63 months after initiation of the treatment (mean, 38 months), 5 of these patients were in complete remission, 2 were in partial remission, 15 had a persistent nephrotic syndrome (with moderate renal failure in 5), and 12 children had end-stage renal failure. Forty-eight percent of the patients with minimal change disease and 30% of those with focal segmental glomerular sclerosis achieved complete remission (p = 0.27). We conclude that cyclosporine in combination with prednisone can induce a complete remission in some children with steroid-resistant idiopathic nephrosis.