Objective: The literature on sexual offenders (SOs) has considered cognitive distortions, defence mechanisms and moral disengagement mechanisms as risk factors in the individual history. Recent literature focuses on how both the concepts of moral disengagement (Bandura et al. 1996) and self-serving cognitive distortions (Barriga and Gibbs 1996) constitute a group of cognitive processes. These processes help to cognitively overcome dissonance between personal moral standards and behavioral transgressions, facilitating violent or, in general, wrong acts (Ribeaud and Eisner 2010). This pilot study investigates moral disengagement mechanisms and cognitive distortions in detained male SO to make treatment effective, taking into account the link between these two constructs. Design and Method: The study sample consisted of 101 males detained in some Italian prisons. Participants were administered a Socio-demographic Data Grid, the Moral Disengagement Scale, the Vindictive Rape Attitudes Questionnaire and the Hanson Supportive Attitudes Questionnaire. Results: Moral disengagement presents a significant correlation with all aspects of examined cognitive distortions (CD) [CD (child): r=.336, p<.01; CD “Sex Kids: r= .278, p<.01; CD “Sexual Entitlement”: r= .375, p<.01; CD (rapist): r= .299, p<.01]. Child molesters’ cognitive distortions are correlated with displacement of responsibility [r= .381; p<.01] and distortion of consequences [r= .278; p<.01]. Cognitive distortions about “sexual entitlement” are correlated with moral justification (r= .284; p<.01), attribution of blame [r= .304; p<.01], euphemistic labeling [r= .274; p<.01], displacement of responsibility (r= .418; p<.01) and distortions of consequences [r= .273; p<.01]. Rapist cognitive distortions present significant correlations with attribution of blame [r= .348; p<.01] and displacement of responsibility [r= .265; p<.01]. Cognitive Distortions, measured by “Sex Kids” subscale, present a moderate correlation with moral justification [r= .222; p<.05], displacement of responsibility [r= .234; p<.05] and distortion of consequences [r= .242; p<.05]. Conclusions: Our results suggest that moral disengagement and self-serving cognitive distortions often are present in the very same cognitive processes and that these processes tend to influence sex offenders’ behaviour (Ribeaud and Eisner, 2010). The correlation between child molester cognitive distortion and Displacement of Responsibility might be explained by an immaturity of the subject and the relative difficulty in relating to an adult preferring contact with child. The correlations between cognitive distortions rapist and Attribution of Blame and Displacement of Responsibility (MDM) could be referred to the offender’s idea that some aspects of the victim (Ex. Being too provocative) justify his violent behaviour against him/her. This study could be interesting to organize specific guidelines for treatment of the offenders and especially for the relapse prevention.