The case of a 64-year-old man who was admitted to hospital with fever, general deterioration and anorexia is reported. For the past 4 years, the patient had been receiving corticosteroid therapy for a chronic inflammatory demyelinating polyradiculoneuropathy. Soon after admission the patient developed respiratory insufficiency as a result of a massive pneumonitis, with severe hypoxia, acute anaemia, acute renal failure and a systemic inflammatory response syndrome (SIRS) requiring admission to the Intensive Care Unit (ICU). All faecal, bronchial, duodenal and urine samples showed Strongyloides stercoralis larvae. Despite antihelmintic therapy and cardiorespiratory support, the patient died from the consequences of irreversible shock. Strongyloidiasis is present worldwide and can be a chronic, essentially asymptomatic infection. This nematode can produce an overwhelming hyperinfection syndrome, especially in patients showing deficient cell-mediated immunity. Strongyloides hyperinfection syndrome is frequently fatal but is potentially a treatable clinical condition. Patients undergoing immunosuppressive therapy or with suspected immunity deficiency (HIV infection, malnutrition, lymphomas, leukaemias or other neoplasia treated with systemic radiotherapy or chemotherapy) must be also monitored for opportunistic Strongyloides stercoralis infection, because clinical manifestation of the systemic hyperinfection syndrome can be rather non-specific.