The distribution and correlates of hypomanic personality traits were examined in a representative sample of 1709 adolescents. Hypomanic traits were assessed with an abbreviated version of Eckblad and Chapman's (1986) Hypomanic Personality Scale. Hypomanic traits were normally distributed and were slightly but significantly higher among females. Test-retest stability over a mean 14-month interval was 0.54. High scores were associated with elevated lifetime rates of mood, disruptive behavior and substance use disorders. Among subjects with no history of mood disorder, hypomanic traits were associated with a broad range of indices of psychosocial dysfunction, both concurrently and at 1-year follow-up. In addition, hypomanic personality traits predicted increased levels of impairment in a number of areas, including depressive and internalizing symptomatology, over the course of the follow-up. Finally, among subjects with a past history of major depression, hypomanic traits were associated with a higher level of depression at the initial assessment, greater symptomatology and impairment during their worst episode, and higher rates of attempted suicide, comorbid disruptive behavior disorders and recurrent major depressive episodes.