A nine-year-old girl was hospitalized because of hypoxemia and anemia. Antibasement-membrane antibodies were present in the serum, but there was no renal involvement suggestive of Goodpasture's glomerulonephritis. Biopsy of the lung showed pulmonary hemosiderosis. In ultrastructural analysis, no lesion of the alveolar basement membrane or capillary endothelial cells was found; however, ferritin-looking deposits were present on alveolar basement membranes and the elastic lamina of arterioles and venules. Mineralogic studies showed these deposits to be made of iron and calcium (this latter element was probably precipitated on altered basement membranes or elastic lamina). Hemosiderin inclusions in the macrophages contained iron but no detectable calcium.