Used the Child Behavior Checklists to develop a classification system to categorize behavior problems of foster children and initiated its validation with 91 foster children in The Netherlands. Identified four groups: normal, aggressive- delinquent-social problems, attention-social problems, and withdrawn-social problems. Found that these taxa corresponded well with Achenbach's general taxomony, but that both taxonomies lack predictive validity for foster care. (Author/KB)