Syphilis, both congenital and acquired, may cause sensori-neural hearing loss. Congenital syphilis presents in two forms: early (infantile), and late (tardive). Acquired syphilis, both secondary and tertiary, may cause deafness. The clinical course of the acquired and congenital forms are similar. Sensori-neural hearing loss with low discrimination scores may affect both ears simultaneously or sequentially, and vestibular complaints are common. A clinical diagnosis can be made on the basis of history, the presence of other stigmata of syphilis, and serological tests, including the FTA-ABS. The histopathology of acquired and congenital forms is indistinguishable and is essentially twofold: first, syphilis may cause a miningo-neurolabyrinthitis with round cell infiltration of the labyrinth and VIIIth nerve as the predominant lesion in early congenital syphilis and the acute meningitides of secondary and tertiary acquired syphilis. Second, syphilis may cause a perivascular round cell osteitis of the temporal bone with secondary involvement of the membranous labyrinth in both late congenital and acquired late latent or tertiary syphilis. Endolymphatic hydrops may be seen in both the congenital and acquired forms. A case of bilateral sequential sudden deafness due to acquired syphilis is presented. A histological diagnosis of syphilitic involvement of the temporal bone was made by incudectomy. Treatment with prednisone and penicillin over a three-month period resulted in return of good cochlear function in one ear.