Anxiety disorders are a major clinical problem in late life; estimated prevalence rates vary from 6% to 10%, and the disease impact is considerable and equal to that of depression. However, anxiety disorders often remain undetected and untreated in older adults. This discrepancy may be accounted for by a combination of patient variables (eg, a lack of help-seeking behavior and long duration of illness) and variables related to current clinical practice (eg, a lack of knowledge regarding late-life anxiety and ageism). Because anxiety disorders usually have an age at onset earlier in life, patients and mental health professionals may be inclined to attribute the anxiety and avoidance symptoms to personality factors instead of a treatable syndrome. Comorbidity with other psychiatric disorders, such as depressive disorder, may complicate the appropriate diagnosis. Identification may be further obscured because the phenomenology of anxiety disorders in older adults tends to differ from the phenomenology in younger adults. Randomized controlled trials have yielded support for the effectiveness of cognitive-behavioral therapy and serotonergic antidepressants. However, both treatments seem hampered by relatively high dropout rates, and the available data are based primarily on a relatively healthy, well-educated, and "young" older population. The dissemination of knowledge regarding late-life anxiety disorders is vital, as evidence-based treatments are available but are still rarely implemented. © 2011 Springer Science+Business Media, LLC.