The 4-factor model of personality vulnerability identifies 4 personality risk factors for alcohol misuse: hopelessness, anxiety sensitivity, impulsivity, and sensation seeking. These personality traits are associated with distinct mechanisms and motivations for alcohol misuse. Individuals high in hopelessness drink to regulate dysphoric affect, while those high in anxiety sensitivity drink to reduce anxiety and to conform to peer expectations. Individuals high in sensation seeking are highly sensitive to the rewarding properties of alcohol, and misuse alcohol to maximize enjoyment. Impulsivity is a broad risk factor contributing to all drinking motives. We hypothesized that personality vulnerabilities would indirectly predict alcohol quantity and problems through specific drinking motives theorized by the 4-factor model. The present study tested hypotheses using a 3-wave, 1-year longitudinal study of undergraduate drinkers (N 302). Data were analyzed using multilevel path analysis. Hopelessness and impulsivity were positively related to drinking motives in the expected fashion. Anxiety sensitivity was related to coping-anxiety and conformity motives only in the between-subjects model (partially supporting hypotheses), while sensation seeking was generally unrelated to all drinking motives and alcohol outcomes (failing to support hypotheses). Enhancement motives predicted alcohol quantity and problems at both levels, coping-depression motives predicted alcohol problems at the between-subjects level only, and coping-anxiety, conformity, and social motives failed to predict alcohol outcomes beyond other motives. Overall, this study partially supports the 4-factor model, with the strongest support emerging for impulsivity and hopelessness. This study suggests that personality traits such as impulsivity and hopelessness may be important targets in prevention and treatment with undergraduate drinkers.