Encephalotrigeminal angiomatosis (Sturge-Weber syndrome) is a rather uncommon congenital condition characterized by the combination of venous angioma of the leptomeninges over the cerebral cortex with ipsilateral angiomatous lesions of the face and sometimes, the skull, jaws and oral soft tissues. Two patients came to the Kaohsiung Medical College Hospital's dental clinic with complaints of localized gingival enlargement or tumor-like swelling. Based on the presence of facial nevus flammeus, examinations of angiography, radiological evidence of calcific densities, and ipsilaterally intraoral vascular hyperplasia in the lip, cheek and gingiva, encephalotrigeminal angiomatosis was diagnosed. Dental management included plaque control instructions, scaling, root planing and periodontal surgery. Recurrence of gingival enlargement in both cases was noted, so periodontal surgery was performed a second time. Close follow up and complete plaque control have kept the periodontal condition fairly well under control in these two cases. We introduce the oral manifestations and the experience of treatments in these two cases.