Fetal blood sampling is a widely used technique for both diagnostic and therapeutic purposes. However, despite the fact that examination of blood smears is a critical step in the study of a large variety of disorders, the place of fetal blood smears analysis has been overshadowed by more sophisticated diagnostic tools such as those offered by molecular biology. Nevertheless, as highlighted by four cases presented in this paper, the role of fetal blood smears examination must be re-emphasized. The recognition of abnormal cytological findings limits the number of possible aetiologies, thus elegantly contributing to the diagnosis without multiplying unnecessary test techniques.