Hard-to-manage preschool boys and comparison boys were studied at age 4 years and followed at ages 6 and 9 years. Externalizing problems at ages 4 and 9 were associated with concurrent family stress, but this relationship was partially mediated by negative maternal control. Cross-lagged regressions indicated that despite the high stability in children's problem ratings, observed negative maternal control at age 4 and self-reported negative discipline at age 9 predicted externalizing problems at age 9 years, controlling for earlier levels of symptoms. Hierarchical regression analyses revealed that problems were more likely to persist in the context of chronic family stress, defined as negative life events, marital dissatisfaction, and maternal depressive symptoms. When problem boys who met diagnostic criteria for Oppositional Disorder and/or Attention Deficit Disorder were compared with boys who were improved by age 9 years, family stress and earlier symptom levels, as well as maternal control differentiated between them. Teacher ratings suggested that these boys were on a clear pathway to persistent problems by age 6 years. A small sample of comparison boys with emerging problems also were living in more dysfunctional families and their mothers reported using more negative discipline at age 9 years.