Reduction of the incidence of sudden death in infants and children depends on prompter recognition, by parents and physicians, of significant symptoms and signs which have preceded such deaths in the past. The author presents an analysis of 17 unexpected deaths at ages ranging from 1 day to 30 months; seven cases are given in some detail. In many cases there was an infection that evolved into fatal septicemia within 48 hours after the first symptom. In three infants he only postmortem finding was mild to moderate pulmonary edema, and the patient had been in apparently normal health before being found dead in the crib. Thus, there remains a significant number of children for whom the precise cause of death cannot as yet be consistently determined.