Sudden infant death syndrome is defined as a sudden death of a previously healthy infant. Even though the medical documentation of these cases has been assessed, autopsies have been made and the place of death has been analysed the cause of death remains unclear. There are three factors that need to be aligned simultaneously in order for SIDS to occur and those include infant stage, infant’s sensitivity and environmental risk factors. Risk factors that have an effect on SIDS development are divided into maternal risk factors, infant risk factors and environmental risk factors. The true cause of SIDS is unknown, but there are many theories that try to determine it. Present theories are connecting the cause with neurological, gastrointestinal, cardiovascular and respiratory systems, but there are also microbiological, immunological and genetical theories. Currently, the neurological theory is the one that is studied best. The diagnosis is set per exclusionem and incorporates place of death analysis, review of medical documentation and autopsy. Rare metabolic diseases and child abuse in term of infanticide can often be declared as SIDS, since there are no pathogically significant differences, so this is something that should be considered. In terms of prevention of SIDS the utmost importance have the American Academy of Pediatrics guidelines, which are at this point proven as the most efficient in reducing prevalence of this syndrome.