Sudden Infant Death Syndrome (SIDS) is a subgroup of unexpected infant deaths that occur during the postneonatal period with relatively consistent clinical, epidemiological, and pathological features. SIDS remains the major cause of death in infants aged between 1 week and 1 year in western countries. While many SIDS risk factors have been and continue to be identified, the diagnosis remains one of exclusion--the definition of SIDS requires a negative history as well as a negative autopsy result. Epidemiological studies have led to the definition of populations with an increased risk for SIDS: prematurely born infants with perinatal risk factors, subsequent siblings of SIDS victims, ALTE infants (10%). Avoidable risk factors such as those associated with inappropriate infants' sleeping position, type of bedding used and sleeping arrangements strongly suggest a basis for further substantial reductions in SIDS incidence rates. The current guidelines for reducing the risk of SIDS are presented.