One nonabusive cause of death in children is sudden infant death syndrome (SIDS). In 2001, the Committee on Child Abuse and Neglect of the American Academy of Pediatrics advised that an infant's death could be ruled as SIDS when all of the following were true: a complete autopsy was performed, there was no gross or microscopic evidence of trauma or significant disease, there is no evidence of acute or remote trauma in a skeletal survey, and other causes of death were adequately excluded. Although a variety of criteria help to standardize the diagnosis of SIDS, the diagnosis of SIDS is subjective, and there is no accepted understanding of the features of SIDS as a distinctive cause of death. Natural diseases that cause death should be distinguished from SIDS. The chapter includes a table that lists various types of diseases under the broad categories of cardiovascular, gastrointestinal system, respiratory, genitourinary system, central nervous system, hematological system, and metabolic/chromosomal. Distinguishing accidental deaths from deaths secondary to child abuse or intentional acts of violence is critical. Since unsafe sleeping circumstances invite accidental deaths in infants, the child victim's sleeping arrangement should be a focus of any investigation of an infant's sudden death. When infants die from accidental drowning, the scene examination and statements made by the caregiver are important. The authors suggest ways in which accidental deaths due to such events as drowning and fire can be distinguished from drowning and fire-related deaths due to abuse/neglect. 2 figures, 4 tables, and 113 references