Pulmonary Langerhans' cell histiocytosis is an uncommon granulomatous disorder of unknown cause. The authors retrospectively evaluated radiographs and computed tomographic findings of five patients with biopsy-proven pulmonary Langerhans' cell histiocytosis. The main structural abnormalities consisted of small nodules and cystic air spaces, but one case showed only pneumothorax due to bullae rupture. Its distribution has been known predominently in the upper lung fields, but in our cases, the lung lesions were distributed in the entire lung fields or predominently in the lower lung fields. We propose that pulmonary Langerhans' cell histiocytosis is extremely variable of its structural abnormalities and distribution.