A 13-years old boy who presented a severe degree of iron-deficiency anemia and diffuse parenchimal infiltrates on the chest roentgenogram is reported. The clinical picture and the presence of hemosiderin laden macrophages in bronchial washing suggest Idiopathic Pulmonary Hemosiderosis (I.P.H.): open lung biopsy confirmed the diagnosis. Immunofluorescence studies showed no deposition of IgG, IgA, IgM and B1C in the lung. The most striking abnormality observed at electron microscopy was hemosiderin deposition in the alveolar-capillary basement membrane. One year after cyclophosphamide therapy was both in complete hematologic and pulmonary remission.