Foster children are at great risk for poor school outcomes. Given that school readiness is a powerful predictor of later school success, the promotion of school readiness skills in foster children is an opportunity for preventive intervention. Results are presented from a preliminary evaluation of a program designed to improve school readiness in foster children. Twenty-four foster children were randomly assigned to the intervention or comparison conditions. The intervention consisted of therapeutic playgroups (twice weekly for 7 weeks during the summer) focusing on social competence and self-regulation skills. Attendance rates for the playgroups are reported. In addition, group differences on data collected before and after the intervention are reported. Intervention group children exhibited increased social competence and self-regulation. Comparison group children exhibited poorer performance in these domains over time. Results are discussed in terms of how the study has informed a current randomized efficacy trial of a school-readiness intervention. (Contains 1 table.)