Severe hemoptysis in cystic fibrosis can be life-threatening because of acute blood loss or because it interferes with sustaining physical therapy of the chest. Hemoptysis was controlled in 19 of 20 cystic fibrosis patients by means of embolization with a combination of 250-590-microns particles of polyvinyl alcohol foam and absorbable gelatin pledgets. Repeat embolization was needed in eight patients to achieve or maintain effective hemostasis. One or more aberrant bronchial arteries were found in seven patients (35%), and a spinal artery branching from a vessel that also supplied bronchial circulation was present in 11 patients (55%). The data suggest that although embolization has a wider applicability than previously reported, care should be taken during angiography to evaluate the bronchial circulation because aberrant bronchial vessels and spinal arteries arising from bronchial circulation are common.