Congenital syphilis is still an important issue in terms of public health. In this prospective study the change in case definition and treatment of congenital syphilis, as well as the addition of a third VDRL to a pregnant woman at her admission to hospital, allowed to improve the detection of congenital syphilis cases to improve, specially in the group of mothers who were infected at the third trimester of pregnancy or close to delivery. In a five-year period (1994-1999) 191 newborn infants of VDRL (+) mothers were studied in the nursery and their clinical and serological (VDRL and FTA-ABS) follow-up was conducted during 15 months. Congenital syphilis was documented in 6/6 cases of the presumptive congenital symptomatic syphilis group and in 3/24 cases (12,5%) in the asymptomatic presumptive syphilis group. No cases were detected in asymptomatic newborn children whose mother had received opportune and adequate syphilis treatment during gestation. Decisions made based on epidemiologic, serologic and clinical records of the mother and her newborn child, are a valid choice to identify those children who are at greater risk of Treponema pallidum infection. This is while there is no specific and sensitive routine diagnostic test available to discard the illness in asymptomatic newborn children, especially when it is not possible to assure a long term follow up.