Wegener's granulomatosis (WG) is an idiopathic systemic disease that usually onsets in adolescence and is rare in young children. Its diagnosis is usually based on the presence of fever with arthralgia and weight loss, associated with symptoms of upper and/or lower respiratory tract involvement and renal disorders. We describe the appearance of a life-threatening lung hemorrhage in the absence of hemoptysis in a 7-year-old girl with a completely negative previous clinical history, who was subsequently diagnosed as having WG. The teaching message is that immediate bronchoscopy with bronchoalveolar lavage seems to be advisable in the presence of severe respiratory distress and bilateral lung as well as renal involvement. When a diffuse alveolar hemorrhage syndrome is demonstrated, WG should be considered among the main etiologies even in a relatively young child without a clinically suggestive history.