Patients with depression almost always suffer from comorbid anxiety or anxiety disorder. It is commonly stated that comorbid depression and anxiety has a worse prognosis, even with adequate therapy, than depression alone. An accumulation of data now make clear that the antidepressants venlafaxine and venlafaxine XR are effective in reducing anxiety in patients with depression. Several of the studies supporting this are reviewed here. Venlafaxine and venlafaxine XR have also been shown to be effective in treating anxiety disorders and venlafaxine XR is presently the only antidepressant approved by the FDA for the specific treatment of generalized anxiety disorder. The effectiveness of venlafaxine in treating anxiety associated with depression and anxiety disorders supports theories implicating abnormal noradrenergic activity as a component of pathological anxiety.