Multiple endocrine neoplasia syndrome type 1 (MEN-1) consists of endocrine tumors of the parathyroid, the endocrine pancreas-duodenum, and the pituitary. Surveillance and screening for the endocrinopathies is recommended in gene carriers. Surgery for MEN-1-related hyperparathyroidism is generally performed as radical subtotal parathyroidectomy, because less surgery is likely to result in persistent or recurrent disease. Multiple endocrine neoplasia syndrome type 2 (MEN-2) consists of medullary thyroid carcinoma, pheochromocytoma, and hyperparathyroidism. Prophylactic thyroidectomy based on DNA testing in the MEN-2 syndrome is considered one of the greater achievements in cancer treatment, because it may be performed before thyroid carcinoma development and provides cure for the patient.