Multiple endocrine neoplasia type 2 (MEN2) is a syndrome characterized by medullary thyroid carcinoma (MTC), unilateral or bilateral pheochromocytoma and hyperparathyroidism. Familial MTC (FMTC) is a subvariant of MEN2 in which affected individuals develop MTC without other manifestations of MEN2. The identification of RET proto-oncogene mutations in MEN2 and FMTC have provided a precise method for identifying gene carriers. This review provides a concise discussion of the use of genetic testing in the management of hereditary MTC, discussing the appropriate use of this new technology with an emphasis on early intervention to prevent death or serious morbidity from this disease.