The behavior of children riding in automobiles with their mothers was assessed by having an observer accompany them on repeated 15-minute automobile rides. Children riding in car seats exhibited very high levels of appropiate or safe behavior, whereas children not riding in car seats exhibited very low levels of appropriate behavior. When car seats were introduced to those children who previously had not used them, the level of appropriate behavior improved dramatically. These results were maintained at three-month follow-up observations. Prevention or reduction of disruptive child behavior on car rides is an obviously important, but previously unreported, benefit of the use of child restraint seats. This fact might very well be used by the pediatrician to further encourage or persuade parents to purchase and use child restraint seats. The use of a child restraint seat to reduce disruptive behavior during automobile rides is an advantage, beyond the safety aspects, of introducing car seats to young children.