Considerable heterogeneity is observed among patients with a Borderline Personality Disorder (BPD). In the present study, we investigated whether we could identify and validate different personality subtypes in 150 BPD inpatients based on reactive and regulative temperament. We identified four BPD subtypes by means of cluster analysis on the Behavioral Inhibition and Behavioral Activation Scales (BISBAS) and the Effortful Control Scale (ECS): an Emotional/Disinhibited subtype (45%) scoring lowest on Effortful Control, an Inhibited subtype (24%) characterized bylaw levels of Behavioral Activation, a Low Anxiety subtype (21%) defined by low levels of Behavioral Inhibition, and a High Self-control subtype (10%) characterized by the highest score on effortful control. The four subtypes were validated by comparing them on clinical symptomatology, comorbid personality disorders, and coping. The current findings offer insight into meaningful differences among BPD patients based on temperamental features, which can offer guidelines for the treatment of BPD patients. (C) 2016 Elsevier Ltd. All rights reserved.