Pediatric onset anxiety disorders (generalized anxiety, social anxiety, separation anxiety) are highly prevalent, and if untreated, are impairing into adolescence and adulthood. In the largest comparative efficacy study remission occurred in about 65% of children and adolescents treated with a combination of a selective serotonin reuptake inhibitors (SSRI) and cognitive behavioral therapy (CBT). In contrast, CBT without an SSRI achieved remission in 35% of children at 3 months and 45% at 6 months-a 30% and 20% difference, respectively. Despite the difference in remission rates, CBT alone is the preferred treatment of most patients and families. Lack of awareness of the significant difference in remission rates and concerns about medication side effects may drive patient and family preference even though SSRIs have a positive safety profile. Critiques of CBT in the above study suggest that CBT was not as effective as it could be due to short treatment duration, restricted family involvement and limited exposure sessions. Would the combination of CBT and an SSRI still be superior to CBT only, if CBT was of longer duration, and included more family involvement and exposure sessions? In the Partners in Care for Anxious Youth (PCAY) study, children and adolescents with an anxiety disorder ages 7-17 years followed in pediatric primary care clinics affiliated with three institution: Lurie Children's Hospital of Chicago, University of California Los Angeles and University of Cincinnati will be randomized to one of two treatment arms; either CBT only or CBT combined with an SSRI (either fluoxetine, sertraline, or escitalopram). CBT in PCAY will be 6 months in duration and include more family involvement, and more exposure opportunities than past trials. The 6-month acute treatment phase will be followed by 6 months of followup. The primary outcome will be anxiety symptom remission and reduction in impairment over 6 and 12-months.