After an extensive educational campaign for the medical community in the area of the Westf. Wilhelms-University Münster five pregnancies at risk for sickle cell anemia and thalassemias were investigated during the first trimester of pregnancy. Following chorionic villi sampling in one case a sickle cell anemia and in two other cases a beta-thalassemia could be excluded. In two additional cases a homozygous beta-thalassemia was proven and in one of the cases the first trimester diagnosis was confirmed in the second trimester by fetal blood sampling. Because of the migration patterns in Europe there is currently a considerable demand for prenatal diagnosis of beta-thalassemias in West-Germany after proper information of the population at risk.