Objective: The purpose of this study is to examine the correlates of child behavior change over time in a replication of the KEEP intervention. Method: The study sample was drawn from the treatment group of the Maryland replication of KEEP (n=65). Change over time was analyzed using multilevel linear mixed modeling. Results: Parents' use of positive reinforcement relative to discipline was associated with the rate of child behavior change among program participants; parents with the lowest initial levels of reinforcement reported the greatest decrease in child problem behaviors. Other participant characteristics were not associated with child behavior change during the study period. Conclusions: The results indicate the efficacy of an evidence-based foster parent training program for reducing child problem behaviors and underscore the utility of teaching parents to use more positive responses relative to discipline as a robust path to improved child outcomes.