Congenital anomalies including chromosomal abnormalities, single gene disorders, and isolated/multiple anomalies due to teratogenic exposure or of unknown origin are an important medical and public health problem. They are the leading cause of stillbirth and infant mortality and an important contributor to childhood morbidity in developed countries. Although as a group they represent a significant health care problem, birth defects are an assembly of numerous individually rare diseases. The available knowledge on their aetiology, epidemiology, prevention, diagnosis and treatment is inadequate. To bring together data on the individuals affected by genetic disorders and to promote the research on the causes and prevention of congenital anomalies, population - based networks of registries for the surveillance of birth defects have been set in different parts of the world. In 1979 started the EUROCAT, European network of registries covering today 1.5 million births per year, or a quarter of births in Europe. It is designed to provide epidemiological data and to identify genetic and environmental factors important in the aetiology of birth defects. Epidemiological data on congenital anomalies reported among live births, stillbirths, and terminations of pregnancy after prenatal diagnosis are recorded. This makes possible the identification of teratogenic exposures and the assessment of the impact of primary prevention and prenatal screening policies and practice at a population level. Recent studies performed by the EUROCAT will be presented, pointing out to the importance of the joint approach to European public health questions concerning surveillance of birth defects.