A 70-year-old male was admitted because of cough and sputum. Chest X-ray showed bilateral interstitial shadows, and usual interstitial pneumonitis was diagnosed by TBLB and BAL. He was followed without medication. The dyspnea increased and the abnormal shadow spread on chest X-ray. Autoimmune hemolytic anemia was newly diagnosed because the RBC count was 195 x 10(4)/mm3, Hb was 8.6 g/dl, and direct Coombs test and warm antibody were positive. In this case, there appears to be a relationship between deterioration of interstitial pneumonia and the on-set of autoimmune hemolytic anemia.