Anxiety disorders are the most common mental disorders both in adulthood and childhood. Recent research indicates that anxiety disorders in childhood and in particular Separation Anxiety Disorder (SAD) increase the risk of mental disorders in adulthood. Despite these results research on SAD is still limited compared to the vast research activity on adult anxiety disorders. The proposed research program will close a gap of current international research: It will test the efficacy of a family based cognitive behavioral treatment program specific for SAD.