Background: Social anxiety disorder is a common mental disorder with high persistence when remained untreated. Access to effective treatment is scarce. Goals: In this study we examined the effectiveness of a 14 week therapist-guided ICBT for patients with social anxiety disorder in routine care. Results: From 2014 to 2017 a total of 169 patients were included in the study, of which 145 started the treatment. On the social anxiety symptoms we identified large within-group effect sizes. We also found moderate effects on the secondary depression symptoms. Significant improvement was reported by 66.2% of the participants and 16.6% had a significant deterioration. Conclusions: Clinical implications from the current study is discussed.