Polymyositis, dermatomyositis, and inclusion body myositis are idiopathic inflammatory myopathies of unknown etiology with autoimmune pathogenesis. For choosing an individual and efficient therapy, diagnostic assignment is an important factor. Therapeutic options in dermatomyositis and polymyositis include corticosteroids and immunosuppressives. Intravenous immunoglobulins are only needed in special cases. In inclusion body myositis, corticosteroids and immunosuppressives are not successful. At the moment intravenous immunoglobulins are the only therapeutic possibility.