Stressful life events and dysfunctional Hypothalamic Pituitary Adrenal (HPA) axis have been implicated in the pathogenesis of psychiatric disorders, including anxiety disorders. This paper attempts to review the existing literature on childhood traumata, recent life events, HPA axis functioning and their relationship in Post-Traumatic Stress Disorder, Panic Disorder, Generalized Anxiety Disorder, Obsessive Compulsive Disorder and Social Phobia. Preclinical and clinical models will be analyzed. Stressful life events seem to have a role in the onset and in the course of these disorders and HPA axis abnormalities have been reported in almost all anxiety disorders. The hypothesis that early stressful life events may provoke alterations of the stress response and thus of the HPA axis, that can endure during adulthood, predisposing individuals to develop psychopathology, will be evaluated.