The increase in convictions for internet-related sexual offending has led to new challenges for treatment providers. By 2005 nearly one-third of all sexual convictions in England and Wales were for internet-related sexual offending. In late 2006 a treatment programme for internet-related sexual offending (the i-SOTP) was given accreditation for use in the community by the National Probation Service (England and Wales). This paper reports on the clinical impact as assessed following completion of psychometric assessments pre- and post-treatment by a sample of 264 convicted offenders. Findings suggest an improvement in deficits concerning socio-affective functioning and a decrease in pro-offending attitudes. These changes are encouraging and support the view that widescale delivery of the programme should be continued. (Contains 6 tables.)