The authors report a case of a 2-month-old girl diagnosed with Beckwith-Wiedemann syndrome (BWS) who was born prematurely and died suddenly in the hospital just before being discharged. BWS is a malformation syndrome associated with an increased risk of childhood tumors. The major features of BWS are macroglossia, abdominal wall defects, and visceromegaly, frequently leading to premature birth. Due to complex inheritance patterns, a predominance of nonfamilial cases, and the variability in expression of the features (termed incomplete penetrance), the risk of delayed diagnosis is evident. Secondary to hyperplastic pancreatic islands, hypoglycemia occurs frequently, and if not anticipated, adequate measures for prevention of hypoglycemic episodes may be delayed, resulting in possible intellectual deficits. The infant presented here died of natural causes: immaturity of the lungs resulting in marginal respiratory function and compounded by increased risk for asphyxia secondary to the enlarged tongue. The clinical history and findings in this infant are discussed in respect to the genetic syndrome with their relevance to medicolegal examination and the causes and manner of death.