Background and Aims: Syphilis and stroke are high prevalent diseases in south Brazil and estimates of concomitance and possible role of syphilis in acute stroke are lacking. Our aims are to estimate the prevalence of syphilis and neurosyphilis (NS) in a cohort of tertiary stroke center. Methods: We reviewed all hospital records of stroke/transitory ischemic attack (TIA) using International Classification of Diseases, 10th revision, at discharge, frequency of syphilis screen, serology positivity, cerebrospinal fluid (CSF) analysis, and prevalence of NS in this stroke population applying CDC criteria. Results: Between 2015 and 2016, there were 1,436 discharges for cerebrovascular events and in 78% (1,119) of these cases, some syphilis screening was performed. We have found a frequency of positive serology for syphilis of 13% (143/1,119), and higher stroke severity was the main determinant for non-screening. Applying standard NS criteria, 4.7% (53/1,119) cases with CSF analysis had NS diagnosis: 8 based on CSF-Venereal Disease Research Laboratory (VDRL) positive and 45 based on abnormal CSF white cells or protein, but CSF VDRL negative. NS VDRL positive cases were younger, had higher serum VDRL title, had more frequent HIV infection, and received NS treatment more often. Demographic and clinical characteristics were not different between NS VDRL negative and non-NS cases. Conclusion: Positive syphilis serology is frequent in patients with acute stroke/TIA in our region. Acute post-stroke CSF abnormalities make the diagnosis of NS difficult in the context of CSF VDRL negative.