Although the cause or causes of sudden infant death syndrome (SIDS) remain unknown, the incidence of SIDS is on the decline in the United States and other countries. This decline has been accomplished largely through public education campaigns informing parents about several important factors associated with an increased risk of SIDS. These factors are prone and side infant sleeping positions, exposure of infants to cigarette smoke and potentially hazardous sleeping environments. Risk-reduction measures such as placing healthy infants to sleep in the supine position, avoiding passive smoke exposure both before and after birth and optimizing crib safety are beginning to lower the SIDS rate in this country. Through patient education, family physicians can further reduce the incidence of the number one cause of death in infants one week to one year old.