In multiple endocrine neoplasia (MEN) syndromes, tumors appear either synchronously or heterochronously in a combination of 2 or more specified endocrine glands. They are broadly classified as MEN 1 or MEN 2 according to the combination of tumors, and are inherited as an autosomal dominant trait. The genes responsible for these syndromes have been identified, making early diagnosis based on familial screening possible. The gene responsible for MEN 1 is located on the long arm of chromosome 11. It is a tumor suppressor gene that codes for menin. The cause of MEN 2 type is a mutation of the RET proto-oncogene on the long arm of chromosome 10. The present article discusses the diagnosis and treatment of these syndromes.