This publication reviews medicolegal investigation of sudden, unexpected pediatric deaths, focusing on systems and procedures in the United States and those deaths which remain incompletely understood or entirely unexplained. It discusses the evolution of our understanding and practice in the area of sudden, unexpected pediatric death investigation, covering the changing philosophies and medical theories as to causation and changing investigative and certification strategies. Procedural guidance for investigation, autopsy and ancillary testing, certification and reporting, and key considerations for prevention, research and working with family members and other professional team members are provided.The path to production of this publication began in 2016 when the National Association of Medical Examiners received a scientific grant from the SUDC Foundation called "Sudden Death in Pediatrics: Consensus for Investigation, Certification, Research Direction and Family Needs" to convene, in collaboration with the American Academy of Pediatrics, an expert panel to identify and discuss the diverse issues and limitations surrounding these deaths and build a foundation for national consensus. The combined effort of a panel of medical examiners, pediatricians, and federal agency representatives, representing the diverse interests of death investigation, autopsy performance, certification, clinical subspecialties (pediatrics, neurology, cardiology, child abuse, injury prevention, infectious diseases, genetics, and metabolic diseases), family needs, prevention, and epidemiology, culminated in this publication.