The aim of this study is to identify the most informative cerebrospinal fluid (CSF) markers in the diagnosis of active neurosyphilis and in surveillance during antibiotic treatment. It is about a retrospective, analytical, epidemiological study over a period of 10 years, from 1 January 2006 to 31 December 2016 conducted in the laboratory of microbiology of CHU HASSAN II of Fez. We have identified 30 cases of neurosyphilis over a 10-year period. All patients were HIV negative. We realised: on the CSF, a cytochemical examination, white and red blood cell count, a total protein and glucose levels. On CSF and serum, VDRL and TPHA tests for the detection of specific antibodies. The CSF study showed 6 cases (20%) of meningitis with cytology varying between 20 and 890 cells / ml predominantly lymphocytic. 40% of cases had hyper-proteinuria with extremes 0.2 and 4.3 g / l, glycorachia was normal in all cases. The initial titration of VDRL and TPHA was positive in 18 (60%) and 22 (74%) in the CSF, respectively, and 20 (67%) and 26 (87%) in the serum. An accurate and simple approach to the diagnosis of neurosyphilis remains elusive and the diagnosis continues to require a thorough assessment of the patient, including exposure to the risk, presence of compatible clinical signs and symptoms, and laboratory. While direct tests (such as microscopy or PCR) are useful in early infection, serological testing remains the mainstay of the diagnosis of neurosyphilis.