Five patients with adrenal insufficiency and large adrenal glands at presentation are reported. Addison's disease was due to adrenal tuberculosis in three patients, with important changes in adrenal configuration on CT reflecting the natural history of the disease. Adrenal infiltration by non-Hodgkin lymphoma and metastatic carcinoma of the lung was the cause of the disease in the fourth and fifth patients, respectively, who developed signs of adrenal insufficiency before the diagnosis of the primary lesion became apparent. Histologic confirmation was established after unilateral adrenalectomy in three patients. In two patients with adrenal tuberculosis, long clinical and laboratory follow-up confirmed the diagnosis. This report indicates that Addison's disease is not infrequently associated with adrenal enlargement. Adrenal size is related to the cause and duration of the various disease states leading to adrenal insufficiency. Moreover, adrenal insufficiency associated with enlarged adrenal glands can be the presenting manifestation of lymphoma or metastasis.