A diagnosis of Apert syndrome, suspected at 24 weeks' gestation after conventional sonography showing turribrachycephaly and syndactyly of hands and feet, was confirmed at 26 weeks' gestation by tridimensional sonography and magnetic resonance imaging. This is only the second prenatal diagnosis reported at mid-trimester, excluding cases published from affected mothers or in connection with a context of recurrence. Additional findings have been collected from tridimensional sonography (mid-facial hypoplasia, downslanting palpebral fissures) and from magnetic resonance imaging (verticalization of the clivus and flattened angle of the cranial base).