The American Thyroid Association (ATA) has revised its guidelines for the management of medullary thyroid carcinoma (MTC) to provide updated evidence-based recommendations. The Task Force identified relevant articles through a systematic PubMed search and created 67 evidence-based recommendations, focusing on the diagnosis and treatment of both sporadic and hereditary MTC. The guidelines emphasize the importance of genetic counseling and testing for patients with MTC, particularly those with specific RET mutations. The Task Force also addresses ethical considerations, such as the duty to warn at-risk relatives and the use of prenatal and pre-implantation genetic testing. Additionally, the guidelines discuss the role of calcitonin and carcinoembryonic antigen (CEA) as tumor markers in MTC. The revised guidelines aim to assist clinicians in providing optimal care for patients with MTC.The American Thyroid Association (ATA) has revised its guidelines for the management of medullary thyroid carcinoma (MTC) to provide updated evidence-based recommendations. The Task Force identified relevant articles through a systematic PubMed search and created 67 evidence-based recommendations, focusing on the diagnosis and treatment of both sporadic and hereditary MTC. The guidelines emphasize the importance of genetic counseling and testing for patients with MTC, particularly those with specific RET mutations. The Task Force also addresses ethical considerations, such as the duty to warn at-risk relatives and the use of prenatal and pre-implantation genetic testing. Additionally, the guidelines discuss the role of calcitonin and carcinoembryonic antigen (CEA) as tumor markers in MTC. The revised guidelines aim to assist clinicians in providing optimal care for patients with MTC.