Using fetal blood sampling, the diagnosis of triploidy can be strongly suspected on the basis of the peculiar hematological picture. Triploid fetuses present with anemia, marked anisopoikilocytosis, and grossly increased mean corpuscular volume, associated with thrombocytopenia and significant platelet anisocytosis. These findings are of considerable immediate diagnostic value. They allow physicians to immediately counsel parents about the prognosis of the fetus. In case of fetal or neonatal distress, this information could orientate decisions about obstetrical and pediatric management while waiting for the definitive diagnosis.