This study examined the underlying factor structure of the DSM-IV criteria to determine whether the diagnosis could be classified into subtypes. It also sought to enhance the clinical interpretation of any identified subtypes by examining their relation to comorbid axis I and II disorders. In 95 treatment-seeking adults (82 women, 13 men), attending a psychiatric outpatient clinic principle components analysis yielded support for three subtypes: ‘affect dysregulation’, ‘rejection sensitivity’ and ‘mentalization failure’. Results of logistic regression analyses indicated that the affect dysregulation subtype was associated with the comorbid diagnosis of generalized anxiety and panic disorder and other cluster B and C personality disorders. The mentalization failure subtype was found to be predictive of posttraumatic stress disorder and other cluster B personality disorders. With further research, confirmation of these subtypes may inform diagnostic revisions and appropriate treatment regimes that are individually designed to target the patients' core symptoms.