BackgroundEffective classification of individuals who commit sexual offences is important for their assessment, treatment, and risk management. Victim age has often been used as a distinguishing factor between perpetrators. ObjectiveThis study aimed to analyse the distinctive psychopathological and criminological characteristics of contact sexual offenders with adult and minor victims. Participants and settingThe study involved 97 adult males who were serving a prison sentence in Spain for at least one contact sexual offence against an adult or a minor. MethodsResearchers gathered data on criminological variables concerning the offender, victim, and modus operandi from prison records and interviews. Participants completed the Millon Clinical Multiaxial Inventory-III (MCMI-III) in a second session, and between-group differences were analysed. ResultsSex offenders with minor victims (SOMV) had significantly lower scores than sex offenders with adult victims (SOAV) on the Antisocial (r = −0.283, p = .005) and Sadistic (r = −0.209, p = .04) personality subscales, and on the Alcohol (r = −0.426, p < .001) and Drug dependence (r = −0.332, p = .001) syndrome subscales. SOAV were also more likely to use violence and/or intimidation, use a weapon, offend against female victims, offend against an intimate partner, commit their offences in public places, serve other ongoing prison sentences, and report a history of alcohol and substance abuse. SOMV were older and more likely to offend against family members. ConclusionsThese results suggest that there are key differences between SOAV and SOMV that should be considered in tailored prevention programmes for each subgroup of offenders.