The purpose of this project was to validate the “Personality Belief Questionnaire, brief version” (PBQ-SF), using a clinical sample (n= 343) and a non-clinical sample (n= 355), with participants between 18 and 60 years of age. Through a confirmatory factorial analysis the factor structure of the nine factor model (schizoid, paranoid, antisocial, narcissistic, histrionic, avoidant, dependent, obsessive compulsive and aggressive passive), and the structure of the seven factors model (dependent/avoidant, obsessive compulsive, narcissistic, autonomous, paranoid, histrionic and schizoid) was tested. The model for measuring the belief factor associated with borderline personality was evaluated separately, since it is composed of items included in the other factors. Conclusion: The best adjustment indicators were those in the nine factor model. The internal consistency of all PBQ-SF scales was good (between 0,71 and 0,90). The clinical sample obtained higher scores than the nonclinical sample in all dysfunctional beliefs, except for the antisocial and narcissistic scales. Men scored higher on the paranoid, antisocial and narcissistic scales.