This study examined the effectiveness of individual exposure combined with cognitive restructuring for social phobia in a clinical setting as well as the influence of sample restriction criteria on the effect size. Participants were 217 unselected patients with a primary diagnosis of social phobia who were treated by 57 therapists in four outpatient clinics of the Christoph-Dornier-Foundation of Clinical Psychology in Germany. Results 6 weeks after the end of therapy showed highly significant reductions in social phobic fears and avoidance as well as in general anxiety and symptoms of depression. However, patients who dropped out during therapy reported a significantly higher degree of depression. Results did not differ between the four outpatient clinics and are comparable with the average effect-sizes reported by meta-analytic studies of controlled efficacy research, using selected patients. Also, restricting the sample according to the selection criteria often applied in research settings did not result in higher effect sizes for the applied outcome measures. We conclude that individual cognitive behavioural therapy for social phobia can be transported from research settings to the field of mental health.