Asymptomatic infection due to Strongyloides stercoralis may result in potentially fatal disease in immunodepressed patients. A case of Strongyloides stercoralis hyperinfection discovered at autopsy in a 55-year-old man who had been undergoing treatment for multiple myeloma is reported, emphasizing the clinical and pathological findings. One day earlier, he presented severe headache, abdominal pain and oliguria, from which he developed acute respiratory failure and septic shock. Because of difficulty in reaching this diagnosis, empirical treatment before starting immunosuppressive therapy may be the best strategy for preventing hyperinfection by this worm.