Cryptogenic organizing pneumonia (COP) generally responds well to corticosteroids with a favorable outcome. Rare cases of organizing pneumonia are rapidly progressive. Yousem et al. studied pathologic predictors of idiopathic bronchiolitis obliterans organizing pneumonia/COP with an unfavorable prognosis. Beardsley and Rassl proposed the name fibrosing organizing pneumonia (FOP). A 74-year-old female non-smoker presented with a 2-week history of dry cough followed by dyspnea and a fever. The clinical course was fulminant, but we successfully performed bronchoscopy. After the diagnosis of FOP, we treated the patient with mechanical ventilation and high-doses of steroids/immunosuppressants, which improved the disease.