Fronto-limbic neural dysfunction has been implicated in the emotional dysregulation and impulsivity seen in borderline personality disorder (BPD). However, it remains unclear whether affected individuals exhibit morphologic changes of the insular cortex, a fronto-limbic integration cortex engaged in emotional regulation and impulse control. This magnetic resonance imaging study examined the insular cortex volume and its relationship to clinical characteristics in a first-presentation teenage BPD sample. No significant difference was found in the insular volume between 20 BPD participants (5 males) and 20 healthy control participants (5 males). There was no association between the insular volume and parasuicidal episodes, trauma exposure, or comorbid Axis I disorders, but the BPD participants with violent episodes during the previous 6 months had a smaller insular volume bilaterally compared with those without such episodes. Furthermore, right anterior insular volume in the BPD participants was negatively correlated with impulsivity score. These preliminary findings suggest that insular cortex volume does not significantly differ in early BPD, but that there might be a relationship with violent and impulsive behavior that is often seen in the disorder. Further studies are needed to clarify whether the potential relationship between the insular cortex volume and impulsivity is specific to BPD.