A 65-year-old man, who had been given a diagnosis of angina pectoris, developed pneumonia 6 months after the initiation of clopidogrel to inhibit platelet aggregation. Chest radiography showed bilateral invasive shadows, and he was admitted to our hospital. He was asymptomatic, but his C-reactive protein and erythrocyte sedimentation rate were elevated. A lymphocyte stimulation test (DLST) with clopidogrel was positive, and bronchoalveolar lavage fluid showed an increase in lymphocytes and a decrease in the CD4⁺/CD8⁺ratio. We noticed no radiologic improvement a week after prednisolone therapy (30 mg/day) with clopidogrel as stated. However, the airspace consolidation had slightly reduced after clopidogrel was halted. We found a few cases of ticlopidine-induced pneumonia, in the literature, but we found no cases of pulmonary adverse events caused by clopidogrel. To the best of our knowledge this is the first case of clopidogrel-induced pneumonia.