Long waiting periods and the deficiency of outpatient therapies stimulated the development of internet-based interventions for a variety of mental disorders during the last years. A Swedish research group developed an internet-based self-help training for patients with chronic tinnitus showing promising results (Andersson et al., 2002; Kaldo et al., 2007; Kaldo et al., 2008). This self-help training was now adapted for German-speaking patients. The present study evaluates the efficacy of this treatment in a randomized controlled trial conducted in Germany. Further aims are a process evaluation of the treatment and the identification of predictors of efficacy.