The participants were selected at random from a larger group convicted of sex offenses against children and who took part in the Sex Offender Treatment Evaluation Program. The offenders took part in semistructured interviews both before and after completing the intervention program. The participants had an average age of 43 years, 7 months. They had committed an average of 1.7 officially recorded offenses; the number of offenses per offender ranged from 1 to 10. Sixty percent had been convicted of an extrafamilial act of abuse. Sixty percent of the victims were female; 83.3 percent were age 12 years or under when the abuse first began. The participants had been convicted of a range of sex offenses. Some of the components of the offenders' deviant fantasies changed after a period of intervention. No significant changes occurred for some offenders; however, considerable differences existed in the individual aspects of self-reported fantasies. Findings indicated that intervention programs need to examine the links between sexual fantasies, masturbation, and offending behavior and that an offender-specific approach to treatment may be beneficial when working with child sexual abusers. Table, appended interview schedule, and 21 references