To explore the relations between the basic dimensions of personality proposed by the five factors model, and measured with the Big Five Questionnaire (BFQ), and personality disorders, considered dimensionally and categorically with the Millon Clinical Multiaxial Inventory II (MCMI-II) in subjects that are in treatment for psychoactive substance abuse or dependency. Material and method: The sample comprises 187 individuals undergoing outpatient treatment for heroin, cocaine, alcohol, cannabis or benzodiazepine abuse or dependency, and who complete both questionnaires simultaneously. Bivariate correlation was assessed between the BFQ dimensions and subdimensions and the MCMI-II personality disorder scales. Subsequently, we made a regression analysis of the BFQ dimensions and subdimensions on each one of the MCMI-II scales. Results: The particular implication of the dimensions of Emotional Stability (Neuroticism) and Energy (Introversion/Extraversion Axis) is seen in most of the disorders, although each one of them displays a peculiar pattern of organization in which all of the five characteristics participate, in line with what has been described in other similar research work, and with the theoretical formulation of each disorder. Finally, there is a diagram of those relationships that, according to a restrictive criterion, are confirmed by both methods, the results being compared with those from similar studies. Discussion: The implication of these results is argued in relation to clinical practice, in addition to a possible dimensional classification, in the future, of the Axis II disorders. We also discuss the limitations of the classifications and the instruments used in the evaluation of these disorders. Conclusions: Personality disorders can be characterized on the basis of peculiar configurations of traits which, as well as having repercussions on the classificatory systems, has particular relevance for the design of psychotherapeutic and pharmacological interventions.