There is a growing body of evidence that social phobia may be treated effectively by either pharmacologic or cognitive-behavioral interventions. but few studies have examined the relative benefits of these treatments. In this study, we examined the relative efficacy of pharmacotherapy with clonazepam and cognitive-behavioral group therapy (CBGT) for treating social phobia. In addition, we examined potential predictors of differential treatment response. Outpatients meeting Diagnostic and Statistical Manual of Mental Disorders (3rd ed., revised) criteria for social phobia were randomly assigned to treatment. Clinician-rated and patient-rated symptom severity was examined at baseline and after 4, 8, and 12 weeks of treatment. All clinician-rated assessments were completed by individuals blind to treatment condition. Patients in both conditions improved significantly, and differences between treatment conditions were absent, except for greater improvement on clonazepam on several measures at the 12-week assessment. Symptom severity was negatively associated with treatment success for both methods of treatment, and additional predictors-sex, comorbidity with other anxiety or mood disorders, fear of anxiety symptoms, and dysfunctional attitudes-failed to predict treatment outcome above and beyond severity measures. In summary, we found that patients randomized to clinical care with clonazepam or CBGT were equally likely to respond to acute treatment, and pretreatment measures of symptom severity provided no guidance for the selection of one treatment over another.