The Hungarian Congenital Abnormality Registry was established in 1962 based on obligatory notification of cases with congenital abnormalities by physicians. However, continuous and expert evaluation of data started in 1970 when the Registry was moved to the National Institute of Public Health. Later several other systems, including the Nationwide Evaluation of Multimalformed Infants, Case-Control Surveillance of Congenital Abnormalities, and Surveillance of Germinal Mutations, were based on the Registry. Data and results of the first 25 years of the Registry are evaluated from three different aspects: 1) evaluation of the originally planned and later adopted missions of the Registry; 2) quality control of the Registry is based on the proportion of misdiagnoses, completeness of notifications, and pathogenetically oriented classification; 3) outcome evaluation indicated the different quality of recorded data in lethal, severe, and mild congenital abnormalities. The data base of the Registry was appropriate to estimate the proportion of preventable congenital abnormalities due to the four different preventive programs and to evaluate the pregnancy outcomes after the Chernobyl nuclear power plant accident.