Consequences of syphilis for mother, pregnancy, fetus and child are considerable, but preventable. Serological screening must be offered at the first prenatal visit, using both a treponemal (eg. TPHA) and a non treponemal (eg. VDRL or RPR) test. When the results are compatible with any type of active syphilis, treatment is required. The treatment of choice is penicillin: benzathine penicillin G, 2.4 million units intramuscular, repeated one week later, and most authors recommend a third dose if a late latent syphilis is suspected, or in case of coinfection with HIV. Women with a proven penicillin allergy can be desensitized. Alternative therapies, such as macrolids, are less well evaluated. Follow-up during and after therapy must not be neglected. In case of Jarisch-Herxheimer reaction, the mother should be managed on an inpatient basis, and the fetus carefully monitored. The VDRL should be repeated (usually every trimester), and therapy be renewed if there is not a significant decrease in titer. The fetus should be followed by serial ultrasound examinations. Finally, the child must be followed up clinically and biologically, and treated in case of congenital syphilis. The residual risk of adverse outcome is increased in case of reinfection, lack of maternal therapy or incomplete treatment, or when diagnosis and therapy are performed late in pregnancy.