We aimed to determine the prevalence of borderline personality disorder (BPD) symptoms in a sample of eating disorder (ED) outpatients and assess how BPD symptoms correlate with severity, distress, and function. A total of 119 individuals were assessed and divided into high BPD symptoms (H-BPD) and low BPD symptoms (L-BPD) using a cut-off score of seven on the McLean Screening for Borderline Personality Disorder (MSI-BPD). Groups were compared on ED diagnosis, age at ED onset, age at assessment, illness duration, body mass index (BMI), ED symptomatology, psychological distress, and psychosocial function. Correlation analyses were performed to assess the relationship between BPD symptoms and these variables. The 45.4% of the participants scored ≥7 on the MSI-BPD, indicating a diagnosis of BPD. There were no differences between the H-BPD (N = 54) and L-BPD (N = 65) groups on age at onset, age at assessment, duration of illness, BMI, or proportion of ED diagnosis. The H-BPD group reported significantly higher ED symptomatology, psychological distress, and poorer psychosocial functioning. MSI-BPD scores were positively associated with these variables. This study suggests a high prevalence of BPD symptoms within outpatients seeking ED treatment, and use of a brief screening instrument for BPD in this group may contribute to a greater understanding of the patient.