We report a case of Churg-Strauss syndrome (CSS) complicated by severe cardiac failure and peripheral neuropathy. Two courses of methylprednisolone pulse therapy were unable to control the disease activity. Repeated intravenous administration of high-dose human immunoglobulin (IVIg) was added together with intravenous cyclophosphamide pulse therapy (IVCY), and the patient's cardiac function and neurological symptoms were gradually ameliorated without any adverse event. Although glucocorticoid and cyclophosphamide comprise the standard therapy for patients with CSS, a number of patients with severe complications appear to be resistant to such conventional treatment. IVIg is thought to be an effective therapeutic option for such patients.