Aims: Problem gambling can create major financial, emotional and sometimes criminal problems for an individual. This study prospectively investigated the association between impulsive behavior at age 7 and the development of life-time problem gambling by adulthood. We also examined the specificity of any observed association between impulsive behaviors and problem gambling by conducting parallel analyses examining the link between respondents' shy/depressed behavior in childhood and later problem gambling. Design, setting and participants: Cohort study of 958 offspring of mothers enrolled in the Collaborative Perinatal Project who participated in an adult follow-up study at a mean age of 39.2 years. Measurements: Multivariable logistic regression models were fitted to determine associations between psychologist-rated impulsive and shy/depressed behaviors at age 7 and life-time self-reported gambling as measured by the South Oaks Gambling Screen administered during the adult follow-up study. Findings: Children who exhibited impulsive behaviors at age 7, compared to their non-impulsive counterparts, were 3.09 (95% confidence interval: 1.40-6.82) times as likely to report problem gambling years later. In contrast, we did not find a significant association between childhood shy/depressed behavior and problem gambling by adulthood in adjusted analyses. Conclusions: Impulsive behaviors at age 7 are a specific and significant risk factor for later problem gambling.