OBJECTIVE: The main purpose of this study was to investigate whether the method of suicide is a valid behavioral marker of a lifetime history of aggression. METHOD: The authors applied the psychological autopsy method to investigate 310 individuals who committed suicide. They used structured clinical assessments and personality trait scales in interviews with family members of the deceased. RESULTS: Violent method was associated with a higher level of lifetime aggression and a higher level of impulsivity. In addition, violent method was associated with lifetime substance abuse or dependence and psychotic disorders. Controlling for age, sex, substance disorders, and other major psychopathology, the authors found that lifetime aggression and the interaction between impulsivity and aggressive behavior remained associated with violent method. CONCLUSIONS: These results support the use of violent method of suicide as a behavioral marker of a higher level of lifetime impulsive-aggressive behaviors.