In this study, we examined the validity of the Personality Assessment Inventory (PAI; Morey, 1991) Aggression (AGG) scales and Violence Potential index (VPI) in 399 male combat veterans presenting for formal evaluation of posttraumatic stress disorder (PTSD). The AGG scales exhibited convergence with other measures of hostility and violence and demonstrated discriminant validity with alternative constructs. When we examined reports of interpersonal violence in the past year, the AGG composite scale displayed substantial incremental validity over the effects of PTSD severity, demographics, a simple dichotomous question regarding violence in the past 30 days, and MMPI-2 (Butcher, Dahlstrom, Graham, Tellegen, & Kaemmer, 1989) scales measuring aggression. The VPI, however, added no unique explanatory power over the AGG composite scale.