This is a clinicopathologic study of 71 hemangiomas of the choroid. The cases were divided into three groups: Group 1 consisted of 45 cases of solitary choroidal hemangiomas (not related to any systemic disease); Group 2 comprised 17 cases with unequivocal evidence of Sturge-Weber syndrome; and Group 3 included 9 cases, 6 of which were classified as "probably Sturge-Weber syndrome." Clinically, many differences were found that established a clear distinction between Groups 1 and 2. Histopathologically, the solitary hemangiomas were well-circumscribed tumors that showed a sharply demarcated pushing margin causing compression of melanocytes and choroidal lamellae. About 70% of these tumors were located temporally (at the posterior pole). In contrast, the lesions in the Sturge-Weber syndrome showed a diffuse angiomatosis involving more than one-half of the choroid, as well as the episcleral and intrascleral perilimbal plexuses. The cause and pathogenesis of these lesions are discussed.