Bucillamine is used mainly in treating rheumatoid arthritis (RA). We report a case of bucillamine-induced pulmonary infiltration with eosinophilia (PIE) syndrome in a 51-year-old woman. When RA was diagnosed, she was treated with bucillamine from December 2000. In April 2001, she was admitted to our hospital because of fever and skin eruptions. Chest radiography and CT revealed both diffuse ground-glass opacity and fine nodular shadows. Laboratory data showed a normal white cell count with eosinophilia. Bronchoalveolar lavage (BAL) studies showed that total cell counts and the proportion of eosinophils were increased, and that the CD4/CD8 ratio of the T-cell subsets was decreased to 0.93. The patch test to bucillamine was positive. After bucillamine was withdrawn, the fever and the abnormal chest shadows improved. We concluded from the patient's clinical course, laboratory data and BAL findings that this was a case of bucillamine-induced PIE syndrome. Since most cases of bucillamine-induced interstitial pneumonitis are lymphocytic alveolitis, we consider that PIE syndrome in such a case is a very rare condition. We concluded that bucillamine should be added to the list of drugs capable of producing PIE syndrome.