Background: Research in the field of personality has tried to recognize themaintraits that reflect the building blocks of personality. For instance, personality dimensions, especially the five-factor model, deals with the field of personality disorder, especially the psychopathic personality disorder. Objectives: The purpose of this study was to analyze and compare the personality traits of psychopathic Prisoners, nonpsychopathic Prisoners, and non-Prisoner patients separated by gender in Tehran. Methods: This descriptive-comparative study was conducted on 355 participants including 202 male Prisoners, 105 female Prisoners, and 48 non-Prisoner patients. All the participants filled out the Hare Psychopathy Checklist and the Revised Neuroticism-Extraversion-Openness Five-Factor Inventory. The data were analyzed by the Pearson correlation coefficient, regression analysis, one-way analysis of variance (one-way ANOVA), and Scheffe’ s post hoc test. Results: Theresultsshowedthat therewasa significant positive correlationbetweenpsychopathyandextraversionanda significant negative relationship between psychopathy and openness, agreeableness, and conscientiousness in male Prisoners. The relationships were significant at the level of 0. 1. Conclusions: By comparing male psychopathic and non-psychopathic Prisoners, female psychopathic and non-psychopathic Prisoners, and non-Prisoner non-psychopathic patients, it was found that psychopathic Prisoners had lower levels of agreeableness, conscientiousness, and openness than the other groups.