A 77-year-old male with no past history was found with his face immersed in a bathtub of water. When he was transferred to our hospital by ambulance, he had disturbance of consciousness and respiratory failure. His condition gradually improved after admission. However, on day 8 after admission he had a high fever and his respiratory condition suddenly worsened. We diagnosed acute respiratory distress syndrome (ARDS) from drowning; thereafter, noninvasive positive pressure ventilation support was started with steroid pulse therapy and continuous infusion of sivelestat. Despite our best endeavors, his condition worsened, and he died of respiratory failure 20 days after admission. An autopsy was performed with informed consent of his family. The lung exhibited the macrofinding of usual ARDS, and microscopic examination revealed an organized phase of diffuse alveolar damage with loss of alveolar epithelium of lots of alveoli, although no hyaline membrane was observed. There have been almost no autopsy cases of ARDS after drowning reported so far; therefore we are reporting this case that we experienced in our hospital.