Strongyloides stercoralis is a soil-transmitted intestinal nematode that may cause long-lived auto-infection in the host. It is distributed worldwide, especially in the tropical and subtropical regions, but has been rarely reported in Korea. Chronic infections by S. stercoralis are mostly inapparent infections that carry nonspecific gastrointestinal and pulmonary symptoms. However, In immunocompromised patients such as those receiving long-term steroid therapy and patients with AIDS or malignant tumors, S. stercoralis can induce hyperinfection by autoinfection. This may lead to increased rate of complications such as resistance to chemotherapy and sepsis. In such cases mortality rate of up to 87% has been reported. We report a case of severe strongyloidiasis in a patient with chronic obstructive pulmonary disease who was receiving long-term steroid therapy. The chief complaint was repeated dyspnea and hematochezia, and strongyloidiasis was diagnosed by the presence of rhabditiform larvae of S. stercoralis in the fecal smear and isolation of filariform larvae from the stool culture. The patient developed septic shock during treatment with albendazole and showed clinical signs of hyperinfection of S. stercoralis. He eventually died despite aggressive treatment.