A sample of 24 adult male sex offenders with histories of sexual abuse completed the Sexual Victimization Survey and a sex offense measure. Participants were recruited primarily from provincial and federal correctional institutions in Canada. Characteristics such as the nature of sexual activities, the duration and frequency of sexual experiences, and participant age and relationship were examined. Results showed trends in the hypothesized direction and revealed various similarities between childhood sexual abuse and adult sexual perpetration. There was a statistically significant relationship between the gender of childhood perpetrators of sexual abuse against offenders and the gender of children they sexually victimized. Most offenders were sexually abused by females during childhood and most committed adult sex offenses against female children. The first childhood sexual abuse generally occurred with an individual who was over 21 years of age. Most sex offenders reported having experienced childhood sexual abuse over a period of years. In addition, most sex offenders had fondling experiences during childhood and fondled children as adults as part of the sexual abuse. With regard to the offender-victim relationship, most childhood sexual abuse experiences involved nonfamily members. Findings suggest the need to address the nature of victimization in the treatment of sexually abused boys and offenders with sexual abuse histories. 31 references