Objective: Borderline Personality disorder (BPD) stands as a hard to treat the disorder. We investigate the insight level differences between BPD patient and results from the literature regarding other hard to treat disordersschizophrenia (SZD) and bipolar disorder (BD). As insight is related to symptomatology, we considered its two aspects: cognitive and clinical. Method: We recruited one hundred and one patients suffering from BPD from DSM 5 Criteria (Mean age = 35.90 years), measured their clinical insight with the Scale to Assess unawareness of Mental disorder and the cognitive insight with the Beck Cognitive insight scale. Results: compared to the literature references BPD patients demonstrated the same BCIS scores as BD and SZD patients but showed better scores than SZD however, equal to BD for SUMD. BCIS score was related to symptomatology level. Limitations: BCIS and SUMD scales were constructed to assess insight in schizophrenia so we need to compare the results with another insight scale. Conclusions: BPD has a good insight level, like BD's. Clinical implications of results and their impact on treatment orientation are discussed.