Most patients with minimal change nephrotic syndrome are steroid responsive and tolerate this medication. However, a substantial number of patients relapse frequently and become steroid dependent. These patients often require treatment with alternative immunosuppressive drugs to maintain remission and minimize steroid toxicity. Previous studies have suggested that mycophenolate mofetil is effective in treating these patients. However, there are limited data on the effectiveness of this agent in pediatric patients, specifically those with steroid-dependent nephrotic syndrome. The purpose of this study was to assess the efficacy and safety of mycophenolate mofetil therapy in children and adolescents with steroid-dependent nephrotic syndrome who failed other treatments. A retrospective chart review was performed on all patients with steroid-dependent nephrotic syndrome. Clinical characteristics, laboratory data and the relapse rate were assessed prior to and during mycophenolate mofetil treatment. Twenty-one patients, ages 2-17 years, with steroid-dependent nephrotic syndrome who were treated with mycophenolate mofetil between 2001-2005 were included in this review. The indication for mycophenolate mofetil use was steroid dependence in 17 and steroid toxicity in 4 patients. The mean duration of treatment was 1.0+/-0.5 years (range: 0.2-2.0 years). Patients treated with mycophenolate mofetil had a reduction in relapse rate from 0.80+/-0.41 to 0.47+/-0.43 relapses per month ( P <0.02). Side effects were mild and mostly gastrointestinal in nature. In 1 child, mycophenolate mofetil was discontinued due to varicella infection and not restarted. The findings indicate that mycophenolate mofetil is a useful adjunctive therapy in the treatment of patients with steroid-dependent nephrotic syndrome. It lowers the relapse rate by 40% and is well tolerated by patients with steroid-dependent nephrotic syndrome.