OBJECTIVES. Borderline personality disorder (BPD) is characterized by a pervasive affective dysregulation. While recent imaging studies demonstrated the neural correlates of abnormal emotion processing in BPD and recently one study reported alterations of the reward circuit in this patient group, the exact neural mechanisms underlying the impact of abnormal emotion on reward behavior remain unclear. METHODS. We therefore conducted an fMRI study in healthy controls and BPD patients to investigate the modulation of the anticipation of reward by simultaneously presented emotional pictures. RESULTS. BPD patients revealed a disturbed differentiation between reward and non-reward anticipation in the bilateral pregenual anterior cingulate cortex if a positive or negative emotional picture is presented simultaneously. In the ventral striatum and the bilateral ventral tegmental area, BPD patients and healthy controls are able to differentiate between reward and non-reward even under emotional stimulation, but BPD patients show a reduced deactivation in the above mentioned regions compared to healthy controls. CONCLUSIONS. Altered emotion processing in BPD patients is likely to affect the reward system. More basic deficits in reward circuitry and other midline regions' level of resting state activity may contribute to this effect.