Background: The incidence of sudden infant death syndrome (SIDS) has declined significantly since the launch of campaigns promoting the back-sleeping position for infants. Each year, death statistics identify 250 cases of SIDS in France, sometimes without the postmortem investigations necessary to confirm this diagnosis. Objective: To determine the number and characteristics of unexpected deaths (UD) among children under 2 years of age in France, the actual proportion of SIDS, explained deaths, and maltreatment, as well as their management in accordance with the recommendations of the French National Authority for Health (HAS). Method: From October 2007 to October 2009, data were collected on all UID occurring in 17 departments at the scene of death and subsequently at the referral center to which the child was transferred. All UID, whether transported or not, were recorded by the SAMU. Results: The inclusion rate was 91% of the 281 cases that occurred. The rate of sudden infant death syndrome (SIDS) in children under 1 year of age was 0.40 per 1,000 live births. Among the SIDS cases in children under 1 year of age included in the study (n=220), the sex ratio was 1.86; the median age was 3 months. An autopsy was performed in 72% of cases involving children under 1 year of age and 88% of those over 1 year of age, but this varied greatly by department. The cause of death was determined following examination in 34% of cases involving children under 1 year of age and 66% of those over 1 year of age, with infectious diseases being the leading cause. Eighteen children under 1 year of age died from asphyxiation in their beds due to improper sleeping arrangements, and in 63 others, one or more known risk factors for SIDS were identified as having potentially contributed to the death. Conclusion: This study highlights the need to renew campaigns on infant sleeping practices and to strengthen referral centers in their role of managing SIDS cases in accordance with HAS recommendations. (R.A.)