Our experience with intravenous immunoglobulin (IVIg) in autoimmune diseases is reported. In 16 subjects with polymyositis and dermatomyositis, IVIg has been given in case of steroid resistance or dependency. Subjects treated with IVIg achieved a clinical and functional remission in a higher percentage (81%), that was maintained after a mean five year follow-up period (p < 0.001), as compared to control group. In twelve subjects with new-onset Churg-Strauss disease, IVIg was added to standard treatment. In these patients, IVIg permitted to achieve a long-term stable remission with a good functional recovery with lower incidence of the steroid-associated side effects. In conclusion, IVIg can be safely employed in subjects with immune-mediated diseases, even in those with severe and refractory disease.