A common approach to study neuronal aspects of emotional reactivity of borderline personality disorder (BPD) is to study the brain response to emotional faces with functional magnetic resonance imaging (fMRI). 10 BPD patients and 10 matched controls were submitted to an emotional discrimination task in which subjects had to identify an emotional face from a neutral face while fMRI data was acquired. BPD patients made more mistakes than controls in the discrimination task when negative faces were involved. The emotional discrimination task activated brain areas that are known to participate in processing of emotional faces (fusiform gyrus, insula and amygdala) regardless of the psychiatric condition. Additionally, BPD showed higher activation than controls in the middle and inferior temporal cortical areas, brain areas that participate in the processing of face features that carry emotional value. Furthermore, activity at this site correlated with impulsivity score in the Zuckerman-Kuhlman Personality Questionnaire. Our findings may be related to cognitive impairment that may be characteristic of the disorder.