We report the observation of a sudden infant death in which autopsy revealed a focal pancreatic lesion called adenomatous hyperplasia. Histopathological and immunohistochemical characteristics of this lesion are detailed. Adenomatous hyperplasia and endocrine cell dysplasia are the two pancreatic lesions responsible for hyperinsulinemic hypoglycemia in infants, with a possible fatal evolution. An organic pancreatic lesion is exceptionally reported in observations of sudden infant death. These observations and ours point out the necessity of a meticulous post-mortem examination of the pancreas in sudden infant death.