There has hitherto been no report describing idiopathic interstitial pneumonia associated with diffuse alveolar hemorrhage, but we herein report one such rare case. A 75-year-old man who had received a diagnosis of idiopathic interstitial pneumonia had been followed in our hospital since 1995, and had been treated with cyclophosphamide since September 1999. He discontinued taking cyclophosphamide without informing us, and two months later he was admitted to our hospital with deterioration of dyspnea on September 13, 2000. Since chest radiography and CT findings demonstrated alveolar infiltrates in the right middle lung field, he was treated with antibiotic agents. Although no deterioration of symptoms occurred, on September 14 he began to suffer rapidly progressive dyspnea accompanied with production of bloody sputum, which eventually developed into full-blown hemoptysis in the evening of September 15. He died of respiratory failure early the next morning. The autopsy findings demonstrated diffuse alveolar hemorrhage, diffuse alveolar damage, interstitial pneumonia, and pulmonary fibrosis.