SUMMARY STATEMENT Based on careful evaluation of existing data indicating an association between Sudden Infant Death Syndrome (SIDS) and prone sleeping position for infants, the Academy recommends that healthy infants, when being put down for sleep, be positioned on their side or back. The most common position currently used in the United States is prone. This recommendation is made with the full recognition that the existing studies have methodologic limitations and were conducted in countries with infant care practices and other SIDS risk factors that differ from those in the United States (eg, maternal smoking, types of bedding, central heating, etc). However, taken as a group the studies are convincing. No reports show an advantage to the prone position with regard to SIDS incidence and there are no data proving, or even strongly suggesting, that sleeping in the lateral or supine position is harmful to healthy infants. Thus, assessment of the risk/benefit balance for prone vs nonprone positioning for such infants favors the latter. It should be stressed that, the actual risk of SIDS for an infant placed prone is still extremely low. There are still good reasons for placing certain infants prone. For premature infants with respiratory distress, for infants with symptoms of gastroesophageal reflux or with certain upper airway anomalies, and perhaps for some others, prone may well be the position of choice. A nonprone sleeping position is recommended for healthy infants only. REPORT Health care professionals frequently are asked how it is best to place an infant down for sleep, prone or supine.