The expansion of the criminal justice system over the last several decades helped to focus attention on children of incarcerated parents, many of whom have parents with substance abuse problems. Since the 1990's, a national grassroots campaign has been underway to make substance abuse treatment an alternative to incarceration for parents who commit non-violent crimes. The question of interest in this article is what evidence there is, if any, that treating parental substance abuse changes children's outcomes. To answer this question, a systematic search was conducted for evidence that parental substance abuse treatment either (1) prevents children from developing serious problems (e.g., substance abuse, emotional=behavioral problems, and delinquency) or (2) ameliorates problems if children have already developed them. The key finding is that existing research is limited to studies primarily of the birth outcomes of children born to pregnant and perinatal substance-abusing mothers. Little is known about how treating parents' substance abuse problems affects the outcomes of older children or children of substance-abusing fathers.