A 65-year-old man with steroid-dependent chronic airflow obstruction presented with progressive dyspnea and weight loss. Travel history included a military tour in southeast Asia. A chest roentgenogram revealed hyperexpanded lung fields with diffusely increased interstitial markings. The Papanicolaou stain of expectorated sputum demonstrated the rhabditiform larvae of Strongyloides stercoralis. Endemic areas of infection include the southeastern United States, Puerto Rico, Central America, the Pacific basin, and central Africa. In recent immigrant groups and veterans of the Vietnam conflict, rates of infection are as high as 6 percent. The hyperinfection syndrome occurs in immunocompromised hosts and is associated with glucocorticoid steroid therapy. This allows massive proliferation of larval forms. Clinical clues include an appropriate travel history (even in the remote past), gastrointestinal symptoms, cutaneous symptoms, eosinophilia, or thrombocytosis. Our patient demonstrated a classic presentation of the hyperinfection syndrome, and the condition responded well to thiabendazole.