This investigation examined the factor structure of 8 well-validated self-report measures that assess traits that fall under the rubric of an "aggressive personality" and then determined how those factor(s) moderated the association between alcohol intoxication and aggression. Participants were 518 (252 men and 266 women) healthy social drinkers between 21 and 35 years of age. Following the consumption of an alcoholic or a placebo beverage, participants were tested on a laboratory aggression paradigm in which electric shocks were received from, and administered to, a fictitious opponent. Aggression was operationalized as the shock intensities and durations administered to the opponent. Results demonstrated a unidimensional factor structure for the aggressive personality traits, which were then combined into a latent variable. The aggressive personality variable moderated the alcohol-aggression relation. Specifically, alcohol was significantly more likely to increase aggression in persons with higher, compared with lower, aggressive personality scores.