This study had two aims. The first was to assess and compare various types of aggressive behavior toward others reported by borderline patients and axis II comparison subjects over time. The second was to determine the best baseline and time-varying predictors of aggressive behavior in these borderline patients. At baseline, a series of interviews and self-report measures were administered to 290 borderline patients and 72 axis II comparison subjects. Measures assessing aggression toward others, axis I and II disorders as well as adult adversity were re-administered every two years over the course of ten years. It was found that borderline patients reported significantly higher rates of verbal, emotional, and physical aggression toward others than comparison subjects but the rates of these forms of aggression toward others declined significantly for those in both study groups. Multivariate analyses indicated that the strongest predictors of adult aggression towards others were severity of adult adversity and a substance use disorder. Taken together, these results suggest that borderline patients commonly report aggression toward others but that this aggression declines significantly over time. These results also suggest that this aggression toward others is most strongly associated with adult experiences of adversity and concurrent substance abuse.