Syphilis is a sexually transmitted disease caused by the spirochete Treponema pallidum, whose incidence has increased significantly in recent years. Some patients may develop sudden hearing loss (SHL) against the background of otosyphilis. The objective of our study was to determine whether routine lues serology is useful in patients presenting with sudden hearing loss. For this purpose, all cases of SHL treated in our hospital during a period of 6years were propectively collected. The frequency of positivity for syphilis in these patients, the treatment received, and their evolution were determined. Of the total number of patients evaluated during that period, 71 underwent serological screening for syphilis, of whom 2 (2.8%) presented positive screening antibodies. In one of them, the RPR was normal and had been treated with lues a few years before. After treatment there was no improvement. The other patient, diagnosed with otosyphilis with unconfirmed suspected neurological disease, showed normalization of hearing after specific treatment. Since it is a potentially curable disease, despite the low overall frequency of syphilis in patients with SHL it is advisable to perform serological screening for syphilis in high risk patients (e.g., incarceration, multiple recent sexual partners, men who have sex with men) or atypical clinical presentation (e.g., concurrent neuropathies).