The objectives of this study were to assess the rates of comorbid anxiety disorders other than PTSD in patients with borderline personality disorder (BPD) and Axis II comparison subjects over ten years of prospective follow-up and to determine time-to-remission, recurrence, and new onset of these disorders. The SCID I was administered to 290 borderline patients and 72 Axis II comparison subjects at baseline and at five contiguous 2-year follow-up waves. The rates of anxiety disorders for those in both groups declined significantly over time, although they remained significantly higher among borderline patients. By 10-year follow-up, the rates of remission for borderline patients who met criteria for these disorders at baseline were high, while the rates of recurrences and new onsets were moderate. These results suggest that anxiety disorders are very common over time among borderline patients. They also suggest that these disorders have an intermittent course among those with BPD.