• Application of the Gunderson-Kolb Diagnostic Interview for Borderlines to a population of psychiatric outpatients suggested two complicating factors in diagnosing borderline conditions in an ambulatory setting: the reduced level of borderline symptoms and the confounding presence of recompensated psychotic patients. Overlap between the Gunderson and Kernberg borderline constructs, which is relatively high in the inpatient setting, is diminished in the outpatient setting. Contrary to expectation, distinguishing borderline patients from patients with other personality disorders was not a source of difficulty.