In order to examine the impulsive profile of a BPD sample with comorbid ADHD, adult patients who met criteria for BPD were assessed for ADHD with the CAADID and the WURS. A high rate of ADHD in the BPD sample was found, with sixty-nine (38.1%) BPD patients diagnosed as having comorbid adult ADHD. BPD-ADHD group had higher rates of general substance use disorder (59.4% vs. 38.4%), antisocial personality disorder (7.2% vs. 0.9%) and obsessive-compulsive personality disorder (21.7% vs. 6.3%). The BPD group without comorbid adult ADHD showed a higher rate of mood disorders (62.5% vs. 37.7%), panic disorders (54.5% vs. 23.1%) and benzodiazepine abuse (18.8% vs. 5.8%). Only in BPD patients without ADHD was comorbid avoidant personality disorder found. BPD patients could be distinguished in two clear subgroups related to the adult ADHD comorbidity. BPD-ADHD patients showed a more homogeneous and impulsive profile while BPD without ADHD comorbidity had more anxiety and depressive disorders. © 2010 The Guilford Press.