Over last decade, road safety attracts increased attention of EU authorities. EU makers believe that new regulations forcing producers to fulfill extremely difficult safety requirement will help to diminish annual road fatalities. One of the latest of such ideas is standardization of side impact resistance of child seats. Since engineers cannot do anything else but to follow the regulations, number of projects aimed toward improvement of child seats side impact resistance has started. The problem is not easy and thus high-end engineering tools have to be used in the design process. One of such tools – a necessity, if one wants to truly understand structure behavior under dynamic working conditions – is numerical analysis of structures. The very basis of effective usage of this technique is reliable model of an analysis subject.This paper presents detailed information on numerical FE model of child seat and its validation based on test results. Effect of modeling techniques and dynamic material behavior on the obtained results is also discussed. Difficulties that arose during real life test are pointed and its influence on FE modeling is showed up.