Twenty-three patients with massive and recurrent hemoptysis were examined with angiography. Particular attention was directed to the internal mammary arteries. Specific causes for the bleeding were tuberculosis (n = 9), aspergilloma (n = 8), bronchiectasis (n = 1), primary systemic amyloidosis (n = 1), congenital and acquired pulmonary venous obstruction (n = 2), chronic pulmonary embolism (n = 1), and bilateral congenital pulmonary artery stenosis (n = 1). Eleven of these 23 patients were treated with systemic arterial embolization, and immediate cessation of bleeding occurred in nine. The recognition of the numerous collateral vessels and anastomoses of the internal mammary arteries is essential for successful percutaneous embolization for hemoptysis. The authors outline these various pathways and collateral vessels.