Objectives: This study investigated the long-term outcomes 1-year after undertaking an Internet-based cognitive behavioural therapy (ICBT) for tinnitus distress in a US population. Secondary aims were to identify the effects on additional difficulties associate with tinnitus and any unwanted events related to ICBT for tinnitus. Methods: A repeated-measures design with 4 time points was used. Participants previously undertaking two randomized ICBT efficacy trials for tinnitus in the US were invited to participate. Of the 200 invited, 132 (66 %) completed the 1-year follow-up questionnaire. The primary outcome was a change in tinnitus distress from baseline at one year post-intervention, as assessed by the Tinnitus Functional Index. Secondary assessment measures were included for anxiety, depression, insomnia, hearing disability, hyperacusis, tinnitus cognitions and health-related quality of life. Results: Undertaking ICBT for tinnitus led to significant improvements 1-year post-intervention for tinnitus severity, with a large effect size (d = 1.06; CI: 0.80 to 1.32). Medium effects were found for anxiety (d = 0.54; CI: 0.29 to 0.79), depression (d = 0.46; CI: 0.21 to 0.70), insomnia (d = 0.47; CI: 0.22 to 0.72), and tinnitus cognitions (d = 0.43, CI: 0.18 to 0.68). Small effect sizes were found for hearing disability, hyperacusis and healthrelated quality of life. Adverse events related to the intervention were only reported by 1 participant. Conclusions: The benefits of audiologist-guided ICBT for tinnitus and tinnitus-related difficulties were maintained 1-year post-intervention with very few adverse events reported. Ways of disseminate evidence-based easily accessible interventions to the general population with bothersome tinnitus should be sought.