Anxiety disorders in children are currently undergoing reclassification. On the basis of a review of the literature, the authors have attempted to point out the main evidence suggesting that a number of risk factors are associated with childhood anxiety disorders. Age and sex seem to influence the risk of anxiety disorder. The child's personality is of central importance: studies of the concept of "temperament" carried out in recent years have underscored that inhibition and introversion in early childhood are associated with an increased risk for anxiety disorders in later childhood. A low socioeconomic setting also seems to be a risk factor whose incidence varies across types of anxiety disorder. Familial risk factors have a very strong effect: children of parents with current or past anxiety disorders with or without mood disorders are at increased risk for anxiety disorders; this risk varies according to the type of disorder in the parents (for instance, the respective roles of panic attacks and avoidance behaviors remain unclear). Lastly, comorbidity is also an important factor: most children with anxiety disorders also have one or several other anomalies, usually anxiety or mood disorders.