This chapter argues that the biopsychosocial interactive model of International Classification of Functioning, Disability and Health for Children and Youth (ICF-CY) can be used as a frame in collaborative problem solving in assessment of children's needs of support, focusing both on the child's needs and the social and physical environment in the preschool. In the version for children and youth ICF-CY the items, on the different levels describe child functioning and components important for participation. In using this model of collaborative problem solving in the assessment and intervention processes, the outcome on child-level is participation in everyday life of the preschool. The chapter provides the collaborative problem solving model involving the ICF-CY. The first step in the model for collaborative problem solving is to describe concrete problems in everyday life for the child in words that are easy to understand. In the ICF-CY framework, the explanations may concern the body, activities and environmental factors.