The findings suggested that, contrary to expectations, caseworkers' reports of externalizing problem behaviors during early adolescence were a more significant predictor of subsequent foster care placement disruption than were the reports of foster parents. Other findings revealed that foster care integration was a key factor in determining placement outcome and was highly predictive of placement stability. Moreover, foster care integration mediated the relationship between behavior problems and risk of placement disruption. The findings suggest that assessing a young adolescent’s relationships with foster families may be more important than assessing problem behaviors in terms of intervening in placement problems. Participants were the caseworkers and foster parents of 179 randomly selected 12- to 13-year-old adolescents living in traditional long-term foster care placements. Participants were interviewed by telephone regarding behavior problems, degree of youth integration into foster home, and predictions of placement outcome using standardized measures. Disruption from the foster home at the time of the interview was prospectively tracked for 5 years. Data analysis involved the calculation of Pearson’s correlation coefficients and logistic regression analysis. Future research should focus on uncovering the processes preceding placement disruption so that foster care systems can be structured to reduce the risk of disruption. Tables, references