Objective: The purpose of this study was to examine the association between paternal alcoholism, paternal absence, and the development and stability of behavioral problems in boys, from kindergarten to the end of elementary school. Method: A sample of 642 boys originating from low socioeconomic status (SES) families was used. Paternal alcoholism was established using the Short Michigan Alcohol Screening Test. Behavioral problems (opposition, hyperactivity, inattention, physical aggression and anxiety) were assessed by teachers' reports when the boys were 6 and 12 years old. Four groups of boys were created on the basis of paternal alcoholism (nonalcoholic, alcoholic) and family structure (intact families, nonintact/father-absent families). Results: Consistent with personality theories of alcoholism, results showed that a propensity for physical aggression and low anxiety best distinguished sons of male alcoholics (SOMAs) from non-SOMAs at both ages (6 and 12 years), even when SES was controlled. In addition, SOMAs were more oppositional and hyperactive than non-SOMAs at both ages. No significant effects were observed for family structure or age, or an interaction between these factors and paternal alcoholism in the multivariate analysis. Conclusions: The results suggest that problem behaviors in SOMAs begin early and persist over time, and that paternal alcoholism and family structure are not associated with changes in boys' behaviors between kindergarten and the end of elementary school in this population, at least in the sample used.