We review evidence from community, primary care, and psychiatric samples to determine whether there are a group of patients who have mixed symptoms of anxiety and depression that are below diagnostic thresholds for either group of disorders. A review of the data strongly suggests that such a group of patients exists and that, despite lacking sufficient symptoms to meet diagnostic thresholds from the revised 3rd edition of the Diagnostic and Statistical Manual of Mental Disorders (American Psychiatric Association, 1987), they often have significant impairment in social and vocational functioning. Because many of these patients also suffer from medically unexplained somatic symptoms, they may be more likely to frequently use nonpsychiatric medical care. Longitudinal studies suggest that persons with mixed anxiety-depression symptoms may represent a population who are at increased risk for more severe mood and anxiety disorders.