Young children in the foster system, who have experienced various traumas, are at risk for mental health problems, particularly externalizing and trauma-related behaviors. Such problems are related to placement instability and future difficulties. Many interventions for foster children take months to implement and tend to target only children with moderate to severe behavior problems. This study presents preliminary findings from a county-wide implementation of Parent-Child Care (PC-CARE), a 7-session dyadic intervention, as a secondary prevention service for all children aged 1–5 years in new foster placements, with the goal of improving children's behavioral adjustment and placement stability. Method: Participants included 153 children aged 1–5 years (50% male) who participated in at least one PC-CARE session with their foster caregivers in the first 90 days of placement. Results: Children who completed PC-CARE showed significant decreases in trauma and behavior symptoms and increases in positive behaviors (i.e., initiative, self-regulation), and caregiver-child relationships from pre- to post-intervention. Children who completed PC-CARE showed more placement stability and fewer placements disruptions to another foster home at one- and six-months post-intervention than children who did not complete PC-CARE. Conclusion: PC-CARE appears to be a promising secondary prevention service within child welfare associated with improvements in children's adjustment to new foster placements and increased placement stability.