Child sexual abuse (CSA) has been recognized as a widespread and devastating problem in our society. Definitional challenges result in a broad range of prevalence rates for CSA varying from 60/0 to 62% for females and 30/0 to 31 % for males (Finkelhor, Araji, Baron, Browne, Peters, & Wyatt, 1986). Although CSA affects our nation's children in epidemic proportions, researchers have found little conclusive evidence regarding CSA precursors. One promising area for exploring the etiology of CSA may be the differential patterns of sexual fantasies in juvenile and adult sex offenders. Abel, Becker, Mittleman, Cunningham-Rathner, Rouleau and Murphy (1987) found that more than 40% of non-familial child molesters reported the development of deviant sexual fantasies prior to sexually offending. Despite variations in offender subgroups, Marshall, Barbaree and Eccles (1991) found that 22% of the offenders experienced deviant fantasies prior to their first sexual offense. Unfortunately, the literature in this area has been quite limited despite its potential. Understanding offender similarities and differences in adult and juvenile populations may be important due to the large proportion of the offender population who begin sexually offending as juveniles and due to the treatment modalities that may be implemented for developmentally different offenders. As many as 500/0 of adult sex offenders have reported sexually deviant behavior beginning in adolescence (Becker, 1988; Ferhenbach, Smith, Monastersky & Deisher, 1986; Marshall, Barbaree, & Eccles, 1991). Juveniles have also been identified as perpetrators in more than half of all cases (Fehrenbach, Smith, Monastersky, & Deisher, 1986). This study investigates the relationship between offenders' sexual fantasies and their use of physical force to sexually offend. This investigation was also designed to examine the similarities and differences between adult and adolescent sexual offenders on these dimensions. Findings reveal an empirical relationship between offenders' fantasies and behaviors in sexual offending. It is anticipated that additional knowledge regarding potential relationships between fantasies and behaviors will assist in assessing and intervening with accused and convicted sexual offenders. Potential implications for clinical assessment and intervention into sexual abuse are discussed as well as the potential for understanding maintenance factors in the continuation of sexual abuse.