Uncontrolled or refractory nephrotic syndrome (NS), seen in a variety of glomerular disorders, leads to end-stage renal disease (ESRD). This study describes the use and efficacy of cyclosporine (CSA) for the treatment of refractory NS in 83 children seen over a 10-year period. The histological diagnosis leading to the NS was focal segmental glomerulosclerosis (FSGS) in 51% (n = 42), IgM nephropathy in 20% (n = 17), membranoproliferative glomerulonephritis in 10% (n = 8), lupus nephritis in 6% (n = 5), human immunodeficiency virus (HIV) nephropathy in 5% (n = 4), minimal change disease in 7% (n = 6), and membranous nephropathy in 1% (n = 1) of patients. During CSA therapy the mean proteinuria of the study population decreased from 5.14 g/24 h (4.80 g/m2 per 24 h) to 1.23 g/24 h (0.92 g/m2 per 24 h) (P < 0.001), the mean serum albumin increased from 2.13 g/dl to 3.53 g/dl (P < 0.001), the mean serum cholesterol decreased from 364 mg/dl to 223 mg/dl (P < 0.001), and the mean serum creatinine increased from 0.77 mg/dl to 1.2 mg/dl (P < 0.01). When analyzed by histological diagnosis, similar significant trends of reduction in proteinuria were seen in all but the lupus group. There was a rise in serum creatinine following the use of CSA in patients with FSGS, lupus nephritis, and HIV nephropathy; however the elevated serum creatinine was only significant in patients with FSGS. At the end of the study period, 20 patients had reached ESRD, of which 11 had FSGS, 5 had lupus nephritis, and 4 were patients with HIV nephropathy. Fifty-four patients were in remission at the end of the study period (48 with proteinuria < 100 mg/24 h and 6 with proteinuria < 500 mg/24 h). In conclusion, among children with refractory NS, CSA induced a remission in a large proportion. However toxicity, as noted by the rise in serum creatinine, was observed in several patients. Since this toxicity may be drug induced or a natural progression of the disease, careful monitoring and close follow-up are essential.