Macroglossia, prenatal or postnatal overgrowth, and abdominal wall defects (omphalocele, umbilical hernia, or diastasis recti) permit early recognition of Beckwith-Wiedemann syndrome. Complications include neonatal hypoglycemia and an increased risk for Wilms tumor, adrenal cortical carcinoma, hepatoblastoma, rhabdomyosarcoma, and neuroblastoma, among others. Perinatal mortality can result from complications of prematurity, pronounced macroglossia, and rarely cardiomyopathy. The molecular basis of Beckwith-Wiedemann syndrome is complex, involving deregulation of imprinted genes found in 2 domains within the 11p15 region: telomeric Domain 1 (IGF2 and H19) and centromeric Domain 2 (KCNQ1, KCNQ1OT1, and CDKN1C). Topics discussed in this article are organized as a series of perspectives: general, historical, epidemiologic, clinical, pathologic, genetic/molecular, diagnostic, and differential diagnostic.