We report a case of biopsy-proven secondary hemosiderosis of the lung in a 58-year-old patient with mitralvalvular heart disease. Both chest radiography and high-resolution CT demonstrated patchy areas of ground-glassopacity; the former indicated that it was in both lungs, while the latter showed inter- and intralobular septalthickening. These findings were reversible when pulmonary venous hypertension was corrected.