Beckwith-Wiedemann syndrome is a rare congenital overgrowth disorder, commonly characterized by macroglossia,gigantism, omphalocele, visceromegaly, and an increased risk of certain embryonal tumor. Most cases of Beckwith-Wiedemannsyndrome were diagnosed after birth on the basis of physical examination features. However, prenatal identification isimportant for proper postnatal management of patients with Beckwith-Wiedemann syndrome, such as hypoglycemia,omphalocele repairment, feeding and airway issues. Of interest, about 5~10% of the patients develop intra-abdominalembryonal malignancies: most commonly Wilms’ tumor, hepatoblastoma and adrenal cortical carcinoma. Fortunately, recentimprovements in prenatal imaging have allowed making Beckwith-Wiedemann syndrome diagnosis prenatally. We nowpresent a case report of a patient with prenatally diagnosed Beckwith-Wiedemann syndrome using prenatal ultrasonographicand magnetic resonance imaging.