Twenty-nine children with nephrotic syndrome were treated with cyclosporine (CsA), 100 mg/m2/day for 6 months and prednisone, 2 mg/kg every other day for 1 month and then subsequently 1 mg/kg every other day for 5 months. A renal biopsy had shown minimal change disease (MCD) in 18 children, focal segmental glomerulosclerosis (FSGS) in 3 children, membranous glomerulonephritis (MGN) in 4 children, membranoproliferative glomerulonephritis (MPGN) in 2 children, and IgA nephropathy in 2 children. All MCD patients went into complete remission during therapy. Five out of 11 steroid-sensitive patients (45.5%) remained in complete remission, while the remaining 6 (54.5%) had 2 to 3 relapses, 19 to 47 months after CsA discontinuation. Two out of 7 steroid-resistant patients (28.6%) were still in complete remission and 5 (71.4%) had 1 to 6 relapses 25 to 49 months after CsA withdrawal. The mean number of relapses in the steroid-sensitive group before and after CsA treatment decreased more (8.5 vs 1.4) than in the steroid-resistant group (8.1 vs 2.4) (p < 0.05). At the most recent examination, 1 of 3 FSGS patients achieved complete remission and 2 had a partial response. Three of 4 MGN patients were in complete remission and 1 was in partial remission. One of 2 MPGN patients achieved complete remission and 1 showed partial remission. Two patients with IgA nephropathy were in partial remission. We compared MCD patients in sustained remission and relapse; the mean CD4/CD8 ratio decreased from 1.5 to 0.9 in the remission group, in comparison with no change in the relapsed group (p < 0.05). The posttreatment renal biopsy showed lesions of nephrotoxicity in 3 of 18 children with MCD whose renal function did not alter after CsA treatment. We concluded: 1) A 6-month treatment of CsA, in combination with a low-dose alternate-day steroid, proved to be effective in maintaining the remission of steroid-sensitive and steroid-resistant MCD patients. 2) The CD4/CD8 ratio can be used as a index to predict remission or relapse after CsA therapy.