Results of this study support previous research with minimal difference found between the 2 sex offender groups with regard to their ranking of the 12 therapeutic factors. It also supports a 2003 research claim that catharsis (emotional cleansing) and self-understanding are most frequently viewed as being the most helpful therapeutic factors and guidance and identification are most frequently seen as being least helpful. Even though it has long been believed that client perceptions of treatment have an impact on treatment outcome, limited studies exist indicating what group participants, specifically sex offenders, view as being helpful in their treatment. In this study, 34 federally sentenced sex offenders in British Columbia were surveyed using 12 therapeutic factors (instillation of hope, guidance, catharsis, interpersonal learning (output), cohesion, self-understanding, interpersonal learning (input), altruism, existential, family re-enactment, identification, and universality) presented in a 60-item questionnaire and a semi-structured interview regarding their perceptions of which therapeutic factors were most beneficial to them in treatment. Sex offenders’ perceptions of therapeutic factors were compared with the perceptions of therapeutic factors reported by other sex offenders. Tables and references