In an unselected sample of over 800 subjects we studied whether behavioral styles at age 3 are linked to personality traits at age 18. We identified 5 temperament groups (labeled Undercontrolled, Inhibited, Confident, Reserved, and Well-adjusted) based on behavioral ratings made by examiners when the children were 3. These groups were reassessed at 18, and their personality styles were measured with the self-report Multidimensional Personality Questionnaire. Results pointed to continuities across time. As young adults, Undercontrolled children scored high on measures of impulsivity, danger seeking, aggression, and interpersonal alienation; Inhibited children scored low on measures of impulsivity, danger seeking, aggression, and social potency; Confident children scored high on impulsivity; Reserved children scored low on social potency; and Well-adjusted children continued to exhibit normative behaviors.