 Youth with a history of maltreatment and foster care placement are at risk for a host of mental health, behavioral, and social problems, resulting in adverse life-course outcomes of great public health significance. This is a 5-year efficacy trial of the Fostering Healthy Futures Program FHF, a preventive intervention designed to promote prosocial development, and to reduce problem behaviors for youth in foster care. FHF is an innovative, culturally-sensitive and multi-component intervention for 9-11-year-old children who have been maltreated and placed in foster care. Through a 9-month intervention that includes screening assessments, one-on-one mentoring, and skills groups, FHF targets cognitive, social and behavioral domains in order to build competencies, improve mental health functioning and quality of life, and reduce problem behaviors and adverse life outcomes e.g. arrests, school dropout, restrictive placements. Assessments with youth, caregivers and teachers will be conducted at baseline pre-randomization, post-intervention, and 1-year follow-up. Data will also include child welfare, educational, and juvenile justice records. A randomized controlled pilot trial of FHF in one county has produced program manuals for the mentoring and skills group components, and evidence of program feasibility, with high recruitment and retention rates. The FHF pilot study has demonstrated positive preliminary effects on putative mediators. A multi-county randomized controlled trial of the FHF program with 256 youth will enable the investigators to: 1 examine intervention effects on both proximal and distal outcomes, 2 examine potential moderators of the intervention, 3 conduct mediational analyses to identify the mechanisms by which the program may enhance outcomes, and 4 conduct within-group analyses. The goal is to design more efficacious interventions, thereby reducing disability, morbidity, and mortality, not only for youth in foster care, but for all high-risk youth. 