A quantitative micro-hemagglutination test for antibodies to Treponema pallidum (MHA-TP) was evaluated in 25 cerebrospinal fluid (CSF) samples obtained from patients with neurosyphilis (NS group) and in 7 CSF samples of patients with reactive serologic tests for syphilis (STS -). These data were compared to treponemal and nontreponemal tests. The MHA-TP was reactive in all of the 25 NS group samples, the FTA-Abs and the complement fixation of Wassermann (CFW) were in 24 and the VDRL. in only 9. In the 7 STS+ samples (STS+ group), the MHA-TP was reactive in 6, the FTA-Abs in all of them and the nontreponemal tests were nonreactive. Results analyses support conclusion the clinical diagnosis of NS must be complemented by cytoproteic dual and immunological treponemal and nontreponemal assays in CSF. The MHA-TP test was as sensitive as FTA-Abs and required less technical and interpretative skills, contributing in association to CFW to NS diagnosis.