Research on the various subtypes of aggression has documented differences in the experience of anger and the expression of angry aggression. Mixed proactive and reactive aggressive individuals exhibit reactive aggression but, unlike reactive aggressive individuals, fail to exhibit angry expressions or physiological arousal. Similar to the proactive group, individuals with psychopathic traits have been found to exhibit emotional underreactivity, and physiological underarousal, while still exhibiting reactive aggression. The present study examined 85 boys (ages 13 to 18) from a detention center. Three groups of aggressive boys were identified via cluster analysis based on the self-report of types of aggressive behavior: a primarily reactive aggressive group (n=29), a mixed reactive and proactive group (n=16), and a low aggressive group (n=40). The three groups were compared on aggressive responding (during a computerized provocation task with low and high provocation trials), on callous and unemotional traits (CU) and on psychophysiological indices of emotional reactivity. All aggressive groups showed greater aggressive responding to high provocation than to low provocation. The mixed aggressive group showed high aggressive responding across all provocation levels, including the no provocation condition, while the reactive aggressive group only showed high levels similar to the mixed aggressive group during low provocation. Unexpectedly, the reactive and mixed aggressive groups reported higher levels of CU traits than the other group. Although the groups did not differ on psychophysiological activity/reactivity, higher levels of CU traits were related to lower skin conductance responses to provocation. Thus, the contribution of high and low CU traits in the three groups to psychophysiological activity/reactivity was examined. Interestingly, the low and mixed aggressive groups who were high on CU traits had lower sympathetic arousal (indexed by skin conductance) and lower sympathetic reactivity to provocation. Thus, the mixed aggressive group showed a general disconnect between their angry aggression (on the provocation task) and their sympathetic reactivity to provocation. However, this was true only if they also showed high rates of CU traits. These results suggest that interventions targeted toward individuals who exhibit particular subtypes of aggression may be more beneficial if the presence of CU traits is also considered.