Diagnosis of late pulmonary syphilis was made in a 72-year old woman on the basis of her medical history of untreated genital syphilis, serological and radiological findings, and the response to therapy. The diagnosis was confirmed two years later by autopsy findings. There was a good correlation between chest x-ray radiography, computed tomography scans, and autopsy findings. In the diagnosis of sarcoidosis and other diseases with similar radiological interstitial lung pattern, syphilitic interstitial pulmonary fibrosis should be carefully excluded.