Psychopathy is a personality disorder that includes interpersonal-affective and antisocial deviance features. The Psychopathic Personality Inventory (PPI) contains two underlying factors (fearless dominance and impulsive antisociality) that may differentially tap these two sets of features. In a mixed-gender sample of undergraduates and prisoners, we found that PPI fearless dominance was related to low Behavioral Inhibition System activity, high Behavioral Activation System (BAS) activity, expert prototype psychopathy scores, and primary psychopathy. Impulsive antisociality was related to high BAS activity and all psychopathy measures. High Extraversion and Openness and low Neuroticism and Agreeableness predicted fearless dominance, whereas high Neuroticism and low Agreeableness and Conscientiousness predicted impulsive antisociality. Although low levels of Agreeableness predicted both PPI factors, their differential relations with other five-factor model traits highlight differences in the way psychopathy manifests itself. Consistent with movements toward assessing personality disorder using the five-factor model, the authors report regression-based equations for the clinical assessment of these psychopathy dimensions using the NEO Personality Inventory--Revised (NEO-PI-R). (Contains 3 tables and 3 notes.)