In October 1989 routine screening for hepatitis B surface antigen (HBsAg) in all pregnant women was introduced in the Netherlands. In order to prevent hepatitis B infection in their offspring all infants of HBsAG-positive mothers receive passive and active immunization. During 1992 about 82% of the estimated total number of pregnant women was screened for HBsAG in the regional laboratories appointed by the National Institute of Public Health and Environmental Protection. Based on data of 1990 it is estimated that about another 10% of the pregnant women were screened elsewhere. The overall prevalence of HBsAG-positivity was 0.41% in 1992, with a range of 0.2% in rural areas to 0.8% in the city of Amsterdam. The overall percentage of HBsAG-positive women is similar to the prevalence found in 1990 and 1991. At present it is unknowh whether the women not reached by the programme belong to the high risk groups for hepatitis B. Passive and active immunization of infants was not guaranteed in these cases. The quality of a screeningprogramme must be monitored continuously. It is therefore imperative that all relevant data are made available. This pertains not only to organizational aspects, but also to administrative and analytical performance of the laboratories. In spite of written agreements a number of regional laboratories did not provide details concerning their analytical performance. In general, the analytical quality is adequate to good and has improved since the start of the programme. Nevertheless, some laboratories should be aware of certain improvement that easily can be achieved.