The blood picture of 100 patients with Addison’s disease was analyzed. Under basal conditions, there was a tendency toward lymphocytosis and neutropenia. Under stress, the blood picture remained fixed. The impaired ability of those patients to show leucocytosis and lymphopenia is attributable to their impaired adrenal function. While large doses of desoxycorticosterone and maintenance doses of adrenal extract had no effect on the blood picture, 17-oxysteroids produce both neutrophilia and lymphopenia. The anemia present in Addison’s disease is normocytic and normochromic.