Substantial evidence from various studies suggests a preeminent role for early adverse experiences in the development of psychopathology. The most recent studies reviewed here suggest that early life stressors are associated with an increased risk for anxiety disorders in adulthood. Early life stress predisposes individuals to develop a number of psychiatric syndromes, particularly affective disorders, including anxiety disorders, and is therefore a significant health problem. This review examines the emerging literature on the relationship between stress, hypothalamic-pituitary-adrenal (HPA) axis function, and generalized anxiety disorder (GAD), panic disorder, and phobias and the role of early life stress as an important risk factor for HPA axis dysfunction. The most consistent findings in the literature show increased activity of the HPA axis in depression associated with hypercortisolemia and reduced inhibitory feedback. In addition to melancholic depression, a spectrum of other conditions may be associated with increased and prolonged activation of the HPA axis, including panic, GAD, phobias and anxiety. Moreover, HPA axis changes appear to be state-dependent, tending to improve upon resolution of the anxiety syndrome. Interestingly, persistent HPA hyperactivity has been associated with higher rates of relapse. These studies suggest that an evaluation of the HPA axis during treatment may help identify patients who are at a higher risk for relapse. These findings suggest that this dysfunction of the HPA axis is partially attributable to an imbalance between glucocorticoid and mineralocorticoid receptors. Evidence has consistently demonstrated that glucocorticoid receptor function is impaired in anxiety disorders. Moreover, normal basal cortisol levels and hyper-responsiveness of the adrenal cortex during a psychosocial stressor are observed in social phobics. Finally, abnormal HPA axis activity has also been observed in generalized anxiety disordered patients. 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.