The effect of anxiety disorder on recovery from impairment following stroke was examined in 142 patients with acute stroke who had follow-up evaluations. Anxiety disorder significantly interacted with depression to influence the severity and course of depression, outcome of activities of daily living, and social functioning. Anxiety disorder, however, did not affect cognitive impairment, which was influenced only by major depression. These data suggest that the existence of anxiety disorders plays an important role in the prognosis of patients with poststroke depression. These data also suggest that depression and anxiety disorder may have different mechanisms.