PURPOSE OF REVIEW: Multiple endocrine neoplasia (MEN) types 1 and 2 are rare hereditary cancer syndromes expressing a variety of mainly endocrine neoplasias. Improved understanding of the molecular and clinical genetics associated with these lesions will likely enhance the diagnosis and treatment of patients with these diseases. RECENT FINDINGS: The MEN1 gene causing MEN1 is a tumor suppressor gene and seems to act as a regulator of the transcriptional machinery. Novel genetic and diagnostic modalities tend to identify neoplastic lesions at an earlier stage, potentially improving outcome and quality of life. Improved understanding of genotype-phenotype correlations in MEN2, caused by a mutation in the RET oncogene, may enable a more individualized treatment for these patients. SUMMARY: Recent advances in molecular pathology, diagnosis, and management of patients with MEN1 and MEN2 are reviewed.