The Strongyloides stercoralis infection is a prominent cause of death in many areas of the world. A 64-year-old man with pulmonary fibrosis was admitted to the hospital because of progressive shortness of breath and increasing cough. The patient had been previously admitted for his illness and had a remarkable immunosuppression due to the use of steroids (CD4+ lymphocytes = 200 x 10(6)/l). Repeated sputum and stool studies were diagnostic for strongyloidiasis. The patient died suddenly from severe cardiorespiratory failure while he was under mebendazole treatment (100 mg b.i.d.). Strongyloidiasis occurs mostly in immunocompromised hosts, as in patients with chronic pulmonary diseases on long-term treatment with corticosteroids, oncology patients under treatment and patients with AIDS.