A 37-year-old woman admitted elsewhere for a high fever, dry cough, stridor, and dyspnea was found in chest radiography and computed tomography on admission to have a thickened bronchial wall with centrilobular nodules in both lower lobes and skipped consolidations in the lower and middle lobe of the right lung. She had been diagnosed with mycoplasmal pneumonia because of high Mycoplasma pneumoniae antibody titer, so clarithromycin (CAM) was administrated. She was referred to us due to hypoxia with obstructive impairment in the pulmonary function test. Ventilation/perfusion radioisotope in the lung scan indicated heterogeneous distribution without mismatch, suggesting bronchiolitis obliterans due to M. pneumoniae pneumonia, so steroids were started. Five weeks of steroid administration ameliorated clinical symptoms, hypoxia, and abnormal shadows, but obstructive impairment diod not disappear completely. Early administration of steroid with antibiotics is required for bronchiolitis obliterans caused by M. pneumoniae. We review cases of mycoplasmal bronchiolitis reported in Japan.