A 71-year-old man was admitted to our hospital with progressive respiratory failure. He was clinically diagnosed with nonspecific interstitial pneumonia (NSIP) 3 years earlier. He was asymptomatic; therefore he was followed monthly without any new drug therapy. Although hypoxemia was seen on admission, no other clinical symptoms or abnormal data suggesting bacterial infection were observed. A chest CT showed new, bilateral, ground-glass opacities. With a diagnosis of acute exacerbation of NSIP, steroid-pulse therapy and oral cyclosporine were started. Despite this treatment, respiratory failure progressed with appearance of hemosputum, and the patient died on the 19th hospital day. Autopsy findings showed severe diffuse alveolar damage accompanied by diffuse alveolar hemorrhage with nonspecific interstitial pneumonia as an underlying disease. It is important to know that diffuse alveolar hemorrhage may occur with acute exacerbation of idiopathic interstitial pneumonia (IIP) including NSIP and to be aware that this condition may indicate a worse prognosis in patients with acute exacerbation of IIP.