The standard therapy for myasthenia gravis (MG) includes steroids and immunosuppressants, which have delayed onset of action and significant side effects. Plasmapheresis and intravenous immunoglobulin have been used mostly for the treatment of severe exacerbations. In the present study we examined the use of intravenous immunoglobulin as maintenance treatment in MG. We included 11 patients with generalized myasthenia gravis. All had severe bulbar and respiratory involvement that required mechanical ventilation in three patients. Intravenous immunoglobulin treatment was initiated at a dose of 400 mg/kg/d for 5 days and followed by maintenance with 400 mg/kg once monthly. Regular medications were continued as necessary. There was significant improvement in all patients, and none required mechanical ventilation over the treatment period of 20.3 months +/- 8.3 (mean +/- SD, total patient years of treatment = 18.7). Steroid and pyridostigmine doses were reduced significantly and steroids were discontinued in two patients. There were no serious side effects related to intravenous immunoglobulin. These results suggest that intravenous immunoglobulin maintenance therapy is a valid modality in patients with MG.