BACKGROUND: The treatment of paraphilias, especially of pedophilia, centers upon cognitive-behavioral psychotherapy and pharmacologic interventions. Two open, uncontrolled clinical studies using the synthetic LHRH-agonist triptorelin suggested that, combined with psychotherapy, antiandrogen treatment reduced deviant sexual fantasies, urges, and behaviors in paraphilic patients. There is a need for further research using controlled, randomized trials to examine the effectiveness of sexual offender treatment including psychotherapeutic and pharmacologic interventions. OBJECTIVE: The aim of this pilot study is to evaluate the efficacy and tolerability of cognitive-behavioral psychotherapy together with intramuscular (IM) 3-monthly injections of triptorelin in adult men with severe pedophilia. STUDY DESIGN AND METHODS: In this multicenter, forensic psychiatric hospital-based, double-blind, controlled, parallel group phase IV trial conducted in Germany, convicted male sexual offenders aged ≥ 18 years with pedophilia, as defined by DSM-IV-TR criteria, will be randomized to receive study-specific psychotherapy together either with triptorelin or placebo for 12 months (total of 4 injections). This is a pilot study, therefore exploratory data analyses will be carried out of three different target parameters: 1. Changes in psychosexual characteristics using the Multiphasic Sex Inventory (scale: sexual abuse of children) 2. Changes in the risk of violent sexual behavior using the Sexual Violence Risk-20 total score 3. Changes in serum testosterone concentration Treatment effects will be assessed by comparing baseline values with those at the final examination (month 12). LIMITATIONS: The absence of real-life stimulants to test for actual recidivism limits possible findings. The study will be conducted in agreement with the European GCP-guideline, all relevant legal requirements, and the legal framework for voluntary treatment of convicted sexual offenders in Germany.