Background: Little is known about narcissistic traits in borderline personality disorder (BPD). This exploratory study aimed to illustrate the associations between total, grandiose, and vulnerable narcissism and gender, diagnostic features of BPD and narcissistic personality disorder (NPD), and psychopathology in BPD patients. Sampling and Methods: The Pathological Narcissism Inventory and psychometric measures for impulsivity, anger, borderline symptom severity, personality organization, depression, and rejection sensitivity were completed by 65 BPD patients. Statistical analyses were conducted using the t test, Pearson correlation, and multivariate regression analyses. Results: Male BPD patients displayed higher narcissistic scores than females (p < 0.01). Grandiose narcissism showed a stronger association with NPD than with BPD (p < 0.01) while vulnerable narcissism was only associated with BPD (p < 0.01). Rejection sensitivity (p < 0.01) and depression (p < 0.001) predicted vulnerable narcissism. Conclusion: Vulnerable narcissism is closely associated with BPD and appears to be more dysfunctional than grandiose narcissism. A comprehensive consideration of both traits is recommended. Our results might help to generate hypotheses for further research on pathological narcissism in the spectrum of personality disorders. Future studies are advised to apply complementary measures and take new diagnostic approaches of DSM-5 and ICD-11 into account.