Sources of therapist stress include the inherent stressors of the therapeutic process; the emotional strain of counseling; clinicians' cognitions, beliefs, and expectations; ambiguity in determining treatment progress and outcome; and operational problems such as excessive workloads and organizational politics. Providing services to difficult clients is also a significant source of therapist stress. Several characteristics of sex offenders make them among the most stressful for clinicians. They generally enter treatment involuntarily; they often deny, minimize, rationalize, justify, and project responsibility for their actions; and they are often unrealistically optimistic about their ability to control their behavior. In addition their detailed stories of violent fantasies and horrific actions can imbue the therapist with awareness of a world of pervasive violence. Moreover, therapists usually lack offender-specific training before beginning to deliver sex offender treatment. Other issues are ambiguity about treatment outcomes, the reality of reoffending, outside expectations, problems in the systems in which clinicians work, and the stigma of working with these offenders. Emotional impacts and boundary and safety issues are central for therapists. Clinicians often develop ambivalent emotions about the offender, experience identification with the victim or aggressor, and accept offenders' minimizations and rationalizations. Clinicians who work with sex offenders need appropriate support to help them maintain their mental and physical health. 30 references