Strongyloides stercoralis hyperinfection syndrome due to the acceleration of the autoinfective cycle of the nematode is a life-threatening form of the infection occurring in immunocompromised hosts. Intestinal ileus, which is commonly encountered in this form, may reduce the bioavailability and thus the efficacy of oral anthelminthic drugs used in the treatment of the S. stercoralis hyperinfection syndrome. We report the efficacy and safety of subcutaneous administration of ivermectin in a patient infected with human T cell lymphotropic virus type I with S. stercoralis hyperinfection syndrome who was unresponsive to an oral combination of ivermectin and albendazole.