The multiple endocrine neoplasia (MEN) syndromes are autosomally dominant inherited disorders in which hyperplastic or neoplastic changes occur in a wide variety of tissues. The specific syndromes are classified according to the endocrine glands affected. MEN type I consists of an aggregation of tumors of parathyroid, pancreatic, and pituitary glands. The association of medullary carcinoma of the thyroid (MCT) and pheochromocytoma is called MEN type II or type IIA, and if combined with mucosal neuromas, intestinal ganglioneuromatosis, and prominent corneal nerves, is named MEN type III or type IIB. Individuals afflicted with MEN type III are characterized by a marfanoid habitus, mucosal neuromas involving oral and ocular tissues, and a number of ophthalmologic findings including prominent corneal nerves, thickened eyelids, and subconjunctival neuromas. These features are easily recognized during the ocular exam, allowing the ophthalmologist to make an early diagnosis of this syndrome prior to the onset of life-threatening manifestations like medullary thyroid carcinoma and pheochromocytoma.