Pulmonary hypertension is an extremely serious and potentially fatal disorder. Although pulmonary hypertension is a potential complication of connective tissue disease, it has been reported rarely in patients with dermatomyositis. Similarly, multiple myeloma is rare in patients with dermatomyositis. We describe a patient with severe pulmonary hypertension who also had features of dermatomyositis and monoclonal gammopathy. To our knowledge, this is the first reported case of a patient in whom all 3 disorders occurred concurrently. Even more striking is the fact that the patient responded to treatment with cyclophosphamide and prostacyclin. He is asymptomatic more than 5 years after treatment was discontinued.