Vascular neoplasms and malformations of the orbit are unusual and fascinating problems. The benign capillary and cavernous hemangiomas are the most common vascular tumors and are classified separately because of distinct clinical and pathologic differences. The capillary hemangiomas progress rapidly in early childhood but have a tendency to regress. The cavernous hemangiomas occur later in life, progress slowly, and often require surgical excision. The orbital aneurysm, venous malformation, arteriovenous malformation, and carotid-cavernous fistula all may cause exophthalmos, visual loss, and other ocular abnormalities. They can be differentiated clinically; however, recent advances in ultrasonography, venography, and arteriography usually permit an exaxt diagnosis. They may be treated surgically, but the mortality and morbidity associated with such surgery must be balanced against the threat of loss of vision.