Abstract – Introduction: Achieving sustainable success in the treatment of anxiety disorders remains a central objective in mental health care. Although research has demonstrated the short-term efficacy of psychotherapy, evidence regarding long-term sustainability is limited. This study examined treatment outcomes 5 years after prediction-error-based exposure therapy. Methods: For 355 patients (616 eligible; 58% follow-up rate), newly collected follow-up data on anxiety symptoms and psychosocial functioning were compared to pretreatment, posttreatment, and 6-month follow-up data from a multicenter clinical trial characterized by high treatment fidelity. Results: Improvements in anxiety symptoms and psychosocial functioning that were evident at posttreatment and 6-month follow-up were largely preserved after 5 years. No significant differences emerged between randomized groups of temporally intensified and non-intensified exposure. From 6 months to 5 years, overall remission rates remained stable, with the majority of patients exhibiting no reliable change in symptom severity. Reliable relapse occurred in 4.9% and reliable new remission in 6.5%. Most patients (63.4%) did not seek additional treatment. Among those who did, depression (64.2%) and anxiety (60.5%) were the most frequently cited reasons, although only a minority (6.0%) sought further treatment exclusively for anxiety. Additional treatment during the follow-up period was associated with higher symptom severity throughout assessments. Conclusion: These findings highlight the sustainability and long-term public health benefits of exposure-based CBT for anxiety disorders. Most patients do not need additional treatments for mental disorders even 5 years after treatment. Nevertheless, further efforts are needed to optimize interventions for those patients who do not achieve remission or experience relapse.