Patients with borderline personality disorder (BPD) report psychotic symptoms, but it has been questioned whether they are intrinsic to BPD. Thirty patients meeting Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV), criteria for BPD were drawn from a specialist personality disorder service. Exclusion criteria included a preexisting clinical diagnosis of nonaffective psychotic disorder. Participants underwent structured psychiatric interview using the Present State Examination (PSE), lifetime version. Approximately 60% of the patients reported psychotic symptoms unrelated to drugs or affective disorder. Auditory hallucinations were the most common symptom (50%), which were persistent in the majority of cases. A fifth of the patients reported delusions, half of whom (three patients) also met DSM-IV criteria for schizophrenia, who were previously undiagnosed. The form of auditory hallucinations was similar to that in schizophrenia; the content was predominantly negative and critical. Persistent auditory hallucinations are intrinsic symptoms of BPD. This may inform current diagnostic criteria and have implications for approaches to treatment, both pharmacological and psychological. The presence of delusions may indicate a comorbid axis I disorder.