This chapter will introduce strategies and review recent findings for a neurobiological approach to the study of personality disorders, focusing primarily on borderline personality disorder (BPD). While there have been important neurobiological studies on other personality disorders including the cluster A disorder of schizotypy, the overwhelming majority of empirical data involves the cluster B diagnosis of BPD. This chapter will discuss a dimensional model of personality, arguing for investigations geared at symptom dimensions rather than the Axis II disorder as a whole. For BPD, the dimensions discussed in this chapter will be impulsive aggression and affective instability, two hallmarks of BPD symptomatology. Research strategies for elucidating the biological underpinnings of these two dimensions will be described in detail. These strategies include neuroimaging and genetics, and pertinent literature will be reviewed.