They were randomly assigned to either a CBT-based self-help treatment (internet-or paper-based, n=68) or a control group (n=38). Some basic information about tinnitus was given to members of the control group, none of which was relevant to treatment. Tinnitus distress and coping abilities were measured as main outcomes. Assessments were performed via self-report inventories at entry and after 3 months. Results of a one-way repeated-measures ANOVA showed that overall tinnitus distress improved in both groups over time (F (104) = 40.27, p=.000, Eta2=.28). In addition, the intervention condition led to more extended improvement than the control condition (F (104) = 12.56, p=.001, Eta2=.11). In both groups use of helpful self-instructions became more likely over time (F(99) = 5.86, p=.017, Eta2=.06) while unhelpful self-instructions decreased (F (99) = 15.59, p=.000, Eta2=.17). Between-group comparison showed that participants in the self-help program reported more helpful self-instructions (F(99) = 5.66, p.=.019, Eta2=.05) and fewer unhelpful self-instructions (F (99) = 5.78, p=.018, Eta2=.06) than controls. Post-hoc tests revealed no differences between internet-based and paper-based intervention and the control condition. The results indicate that the self-help manual leads to additional improvement regarding tinnitus distress and enhances copingabilities. To further investigate the long-term effects of the program on tinnitus distress a 6-month follow-up measurement is planned. Fatigue is a symptom common to many chronic illnesses. It is also an unpleasant side-effect of medical interventions such as curative treatment for cancer. Even when fatigue is not one of the key presenting symptoms, it if often described by patients as one of the most disabling and difficult to manage. This symposium will present a series of treatment trials which have looked at cognitive behavioural therapy (CBT) treatment packages for fatigue in three different patient groups, cancer, multiple sclerosis (MS) and chronic fatigue syndrome (CFS). Four key questions will be addressed during the symposium talks and discussion 1. Is CBT an effective treatment for fatigue across conditions? 2. Can CBT for fatigue be offered in a more cost-effective and potentially widely available web-based format? 3. What are the key mediators of CBT in the treatment of fatigue? 4. How can our understanding of mechanisms of change in CBT help maximise our treatment effects? The first talk presents data from a randomised controlled trial of CBT versus a brief nursing intervention for the reduction of fatigue during curative cancer treatment. CBT is shown to be the only effective treatment. Interestingly, increases in physical activity do not mediate the treatment effect. The second study shows that therapist driven CBT is useful for the treatment of fatigue in MS. Mediation analysis suggests that the key mediator of change in fatigue is change in patients' negative beliefs about fatigue. The third study discusses the development of a web-based intervention to treat MS fatigue. Data from a pilot RCT suggests that this approach can substantially reduce fatigue and is economical, but the effect size is smaller than therapist delivered CBT. The final presentation looks at both mediators and predictors of the effectiveness of CBT in a sample of patients undergoing treatment at a specialised fatigue clinic. Catastrophising about symptoms is the key treatment mediator, while extreme behavioural or cognitive avoidance predicts worse treatment outcome. The symposium discussion will focus on the best way to package CBT for different patient groups. How the findings from these talks can help us understand models of fatigue and treatment processes will also be addressed.