A periungual wart caused pain and roentgenographic evidence of bone destruction in the right index finger of a 40-year-old man. When conventional therapy failed, 2,250 rads of x-ray therapy was given and the wart disappeared. Roentgenograms of the finger one month after clinical cure showed early bone remineralization. Subungual epidermoid carcinomas and keratoacanthomas may cause destruction of the underlying bone, but both of these diagnoses could be excluded in this patient. We believe that this is the first report in which a common wart is shown to cause underlying bone destruction.