Renal function evolution during idiopathic nephrotic syndrome depends on treatment toxicity. Cyclosporin is effective as a steroid-sparing agent but patients are dependant on this drug, which can lead to renal toxicity. Mycophenolate mofetil, a widely used drug in organ transplantation, has short-term beneficial effects in glomerular diseases, including idiopathic nephrotic syndrome. Little is known about mycophenolate mofetil in children and long-term evolution. We analysed a cohort of 12 children with steroid-dependant nephrotic syndrome due to minimal change disease in remission with cyclosporine therapy. They were switched to mycophenolate mofetil, when renal toxicity was diagnosed. We evaluated the number of relapses, tolerance of this new treatment, renal function and body mass index under mycophenolate. After a follow-up of 31.25 months, mycophenolate mofetil alone was effective in preventing relapses in eight patients, without side effects. Renal function significantly improved and the final body mass index decreased. Three patients relapsed on discontinuation of mycophenolate mofetil. The results suggest that mycophenolate mofetil is effective and safe in preventing relapses in steroid-dependant nephrotic syndrome. Furthermore, switching from cyclosporine to mycophenolate mofetil restores renal function. Therefore, mycophenolate mofetil might be considered as an alternative to cyclosporine, to preserve renal function and spare steroids during idiopathic nephrotic syndrome in children.