The biochemical screening from maternal serum for Down syndrome and other chromosomal anomalies has been introduced in 8 centers in Hungary since 2002. In practice basically two types of screening are applied: the early combined screening (10-13 weeks of gestation) and the triple test (15-18 weeks of gestation). The early combined screening has been applied in 5 Hungarian centers, where testing has been carried out in 10000 pregnancies. The early combined test significantly increased the effectiveness of screening for chromosomal defects as compared to the measurment of nuchal translucency, while the false positive rate in the case of pregnant women under 35 years of age was not higher than 3%. The triple test was carried out in 8 centers where altogether more than 33000 pregnancies were screened. In the case of the triple test in pregnant women under 35 years of age the fals positive rate was not higher than 5%.