The adrenal cortex has become a focus of interest in studies of human cancer since Huggins and co-workers1 in the last 10 years demonstrated the therapeutic effects of surgical adrenalectomy. Recently, so-called "medical adrenalectomy" after cortisone administration also has been thought to influence favorably the courses of certain patients with metastatic cancer.2 No significant morphologic alterations of the adrenal have been observed accompanying the common types of cancer, although a variety of abnormal cortical secretion products has been identified, particularly by Dobriner and his associates.3 The present analysis is part of a pathologic study of more than 1000 autopsied cancer patients, with particular attention to persons with multiple primary cancers. The findings concerning adrenal cortical hyperplasia demonstrate (1) the types of neoplasms more and less frequently associated, (2) the higher incidence of the adrenal cortical hyperplasia accompanying multiple primary cancers, and (3) the lower incidence in noncancer