Many individuals with borderline personality disorder (BPD) receive medical treatment in clinical practice, although to date, there are no drugs specifically available for BPD. The recent Cochrane guideline suggests a benefit from using second-generation antipsychotics such as olanzapine or aripiprazole; nevertheless, side effects limit their use. Asenapine is a novel FDA-approved atypical antipsychotic for schizophrenia and bipolar disorder. However, it has not yet been tested for BPD. The goal of this observational open-label study was to assess the safety, tolerability and efficacy of asenapine in a series of cases of patients with BPD. Twelve individuals with BPD were recruited and treated with asenapine during an 8-week period. Eight individuals completed the study; a significant improvement was observed in the CGI-BPD (P<0.001) and BSL-23 (P<0.048) scales for BPD symptomatology. Besides, there was a significant improvement in the general psychopathology domains (BPRS, P<0.004), whereas no significant differences were observed in depressive symptoms. No serious adverse effects were reported and a significant weight reduction was observed (P=0.002). Asenapine appears to be a safe and effective agent in the treatment of patients with BPD, especially when other alternatives are not tolerated. These preliminary findings should be replicated in a controlled clinical trial.