Severe mononeuritis multiplex in systemic lupus erythematosus (SLE) is quite rare and almost always accompanied by evidence of active disease in other organs, although occasionally it may be the presenting feature of the disease. We describe here two patients with SLE who presented a severe mononeuritis multiplex secondary to a necrotizing vasculitis which respond successfully to therapy with intravenous cyclophosphamide, and review the literature of similar cases.