Antipsychotics are recommended for the treatment of impulsive dyscontrol and cognitive perceptual symptoms of borderline personality disorder (BPD). Three reports supported the efficacy of oral risperidone on BPD psychopathology. Paliperidone ER is the metabolite of risperidone with a similar mechanism of action, and its osmotic release reduces plasmatic fluctuations and antidopaminergic effects. The aim of this study is to evaluate efficacy and safety of paliperidone ER in BPD patients. 18 outpatients with a DSM-IV-TR diagnosis of BPD were treated for 12 weeks with paliperidone ER (3-6 mg/day). They were assessed at baseline, week 4, and week 12, using the CGI-Severity item, the BPRS, the HDRS, the HARS, the SOFAS, the BPD Severity Index (BPDSI), and the Barratt Impulsiveness Scale (BIS-11). Adverse events were evaluated with the DOTES. Paliperidone ER was shown to be effective and well tolerated in reducing severity of global symptomatology and specific BPD symptoms, such as impulsive dyscontrol, anger, and cognitive-perceptual disturbances. Results need to be replicated in controlled trials.