Introduction Syphilis consists of an STD (sexually transmitted disease) of bacterial aetiology, featuring a serious public health problem. The objective was to describe the prevalence of congenital syphilis in a hospital of the Public Health System – Rio de Janeiro, Brazil.

Methods Design. A descriptive and observational research of quantitative and retrospective nature. Data collection. We collected data from the medical records. Statistical analysis. The data were processed by simple frequency measures (absolute and relative).

Results We analysed 175 notified CS (congenital syphilis) cases in 6274 deliveries (prevalence of 2,7%). Some women at the time of delivery had their data collected, were affected by syphilis during pregnancy and prenatal care. About of 80.0% of women with syphilis performed prenatal care. There were carried out positive 276 tests (VDRL) in the Hospital Estadual da Mãe by the women in the study, 104 (59.42%) in prenatal care and 172 (98.28%) at time of delivery, when the test was repeated for all the participants. The distribution of the number of sexual partners of syphilitic pregnant women that made treatment during prenatal care of pregnant women was very impaired because of very high missing values.

Conclusions At the end of this study we found that even though the Ministry of Health has established a program together with the World Health Organisation, the goal of reducing the number of cases of congenital syphilis has not yet been reached. We have problems with the prenatal care, lack of effective screening program and monitoring of the pregnant woman. The findings of CS in the State Hospital of Mother separated for investigation were considered high in relation to the proposal drawn up by the Ministry of Health (1/1,000).