The relationship between bronchial carcinoids and hormonal disorder is reviewed in the light of a study of 24 patients with carcinoid tumors of the bronchus. In this series, two patients presented with manifestations of the polyendocrine disorder. The common origin of carcinoid tumors and other APUD cells from neural crest ectoderm provides a common denominator in the association of carcinoid tumors of the bronchus and adenomas, or carcinoma of associated endocrine organs.