Patients with chronic adrenal insufficiency suffer from reduced quality of life and increased mortality. An association between mortality and adrenal crisis is assumed. The frequency of adrenal crisis is about 8/100 patient years. The main causes are infectious disease. Pathophysiology is poorly understood to date. An association with an exaggerated inflammatory response due to a lack of glucocorticoid modulation as well as mineralocorticoid deficiency and diminished adrenomedullary function are discussed. The therapy of adrenal crisis includes prompt parenteral administration of hydrocortisone combined with isotonic saline. To prevent adrenal crisis, patients are equipped with an emergency card and set and educated in glucocorticoid dose adjustment.