In this context, many doubts have been expressed about the possibility of adequately assessing and treating sex offenders in institutions. Since 1991, the Prison Service in England and Wales has progressively implemented a systematic strategy for treating imprisoned sex offenders. At the heart of this strategy is a structured group work program designed to be delivered by paraprofessional staff. The program includes elements that help offenders confront their cognitive distortions with respect to sexual interests and activities. By April 1994, over 700 sex offenders had completed the program. Issues associated with sex offender treatment in the prison setting are explored, and factors affecting offender acceptance or refusal of treatment are examined. The dangers of institutional reinforcement of attitudes in treatment refusers are also considered. 7 references, 3 tables, and 1 figure