1 ABSTRACTThe compulsory use of child restraint systems (CRS) in cars which came into force on 1st April 1993 led to a considerable increase in the belting rate of children in Germany, but between 30% and nearly 60% of the children aged 0<12 years are only restrained by an adult belt (lap or three-point belt).On the basis of a new accident material of the German Motor Insurers (593 restrained children 0 to 12 years involved in 448 car accidents) the injury risk of children being belted with an adult belt only is compared to those injury risks of children being restrained in different types of CRS (415-point belt, 3-point belt, impact shield, booster cushion). The form of restraint „child with an adult belt only” involves disproportionately high risks.In retrospective accident studies it is relatively difficult to get detailed information about the frequency and the exact kind of CRS misuse. Therefore 250 users of CRS were observed and interviewed. Only in one third of these observations the CRS were correctly mounted; depending on different types of CRS the misuse rates lay between 20 and 90%.To check up the effect of the most frequent and most severe kinds of misuse 20 crash tests with wrong fitted CRS were carried out; for this reason tests with an ECE sled and with a cut-off car body have been performed. Depending on the kind of CRS a partly considerable reduction of the safety effect of CRS could be observed in case of misuse. Protection against misuse by a proper design has to be given highest priority for the safety improvement of future CRS.