Sudden, Unexplained Death in Childhood (SUDC) is a term that encompasses apparently natural deaths in children over one year of age with no discernible cause despite a thorough assessment. Definitive underlying causes vary but most cases remain largely unexplained. Research has furthered the view that SUDC is not an accident, but rather a sentinel medical event for which a thorough postmortem investigation is indicated. Emerging evidence in genetics, neurology, and neuropathology point to heterogeneous causes that in some cases share features of recognized diseases.