This paper describes the relationship between several types of anxiety disorders and tobacco use. Possible explanations of those relationships are presented. Nicotine probably modulates the function of pathways involved in stress response and anxiety in the normal brain, which results in alterations of anxiety levels. Anxiety disorders do not seem to be related to a particular form of tobacco consumption. However, smoking is more frequent in these patients and seems to be implicated in some of their coping strategies. Understanding neurobiological and behavioral mechanisms underlying the association between smoking and anxiety disorders may improve physician's ability to assist smokers in their efforts to quit.