The vascularization of growing and regressing bronchogenic carcinomas was analyzed by comparison of postmortem angiographic and histologic investigations of bronchial arteries in 20 autopsy lungs with bronchogenic carcinoma. Vascular findings in bronchial arteriograms range from correct orientation of proliferating vessels to convoluted patterns of vascular growth during the early phases of tumor growth. Later spotty or smudgy extravasation may be seen in necrotic tumor areas, and increased vascular anastomoses appear between the nutritive and functional pulmonary circulations. Characteristic findings in angiography may be correlated, to a certain extent, with size and histologic type of the tumors. Our findings emphasize the role of nutritive pulmonary vessels in the vascularization of bronchogenic carcinoma at different stages of its development.