We treated five, three steroid resistant and 2 steroid dependent nephrotic syndrome with oral cyclosporin A and prednisolone. All children received more than eight weeks course of prednisolone, and were in a critically ill status from their nephrotic syndrome and by steroid-toxic side effects. Cyclosporin A was started at 7 mg/kg/day and titrated to maintain serum level of 150-250 ng/ml. Prednisolone was given initially at a dose of 1 mg/kg/day x 1 month, subsequently at a dose of 0.4 mg/kg/day x 1 month, then 0.2 mg/kg/day x 4 months. After a total course of six months, cyclosporin A was tapered to 3.5 mg/kg/day. Prednisolone was maintained at a dose of 0.2 mg/kg/day. Renal biopsies of the 3 steroid resistant children showed membranous glomerulonephritis with focal segmental glomerulosclerosis, focal segmental glomerulosclerosis and IgM nephropathy respectively. These three cases all went into complete remission within four weeks. Among them, one case relapsed twice within one year. Renal biopsies of the two steroid dependent children showed minimal change and focal segmental glomerulosclerosis respectively. These two cases went into complete remission within three weeks sustained up to a year. Side effects of cyclosporin A were observed in one patient with gum hypertrophy and two patients with hirsutism. Other side effects were not found. After cyclosporin A treatment for one year, the renal biopsy of the relapsing patient showed no interstitial fibrosis or tubular atrophy. In conclusion, cyclosporin A was found to be effective in steroid resistant and dependent patients. The duration of cyclosporin A treatment is so far unknown. It needs further evaluation in the future.