The child welfare and substance abuse systems are integrally linked through the children and families they both serve. There is a dearth of knowledge, however, on how children who have experienced foster care fare when they are treated for substance abuse issues as adults. This article presents an exploratory study using the Alcohol and Drug Services Study (ADSS) data set. To pursue a set of exploratory questions, adults in substance abuse treatment who were formerly in foster care were matched with a group who had not experienced substitute care. Their experiences before and after treatment were compared. This article presents the methodological and substantive findings. (Contains 2 tables and 2 footnotes.)