Hereditary medullary thyroid cancer syndromes comprise familial medullary thyroid cancer (FMTC) and multiple endocrine neoplasia types 2A and 2B. Hereditary medullary thyroid cancers have an autosomal dominant pattern of inheritance and are caused by activating germline point mutations in the RET proto-oncogene. Evaluation of the onset, extent, and progression of hereditary medullary thyroid cancer associated with specific RET mutations has enabled clinicians to treat patients based on the level of risk associated with their specific mutation. Children identified by RET screening to be at risk for the development of medullary thyroid cancer can be treated with prophylactic thyroidectomy before developing the disease. This review covers the diagnosis, evaluation, timing of surgical management, and optimal follow-up of patients with hereditary medullary thyroid cancer syndromes.