International Journal of Preventive Medicine (Int J Prev Med)2008-78021292021102025352535ENDepartment of Pediatrics, School of Medicine, Child Growth and Development Research Center, Research Institute for Primordial Prevention of Non Communicable Disease, Isfahan University of Medical Sciences, IsfahanPediatric Diseases Research Center, Guilan University of Medical Sciences, RashtPediatric Diseases Research Center, Guilan University of Medical Sciences, Rasht20211020Congenital hypothyroidism is one of the most common endocrine disorders in infants and children. Thyroid hormone effects the function of most organs of the body. In premature neonates, thyroid abnormalities are very common but transient. There is a significant difference between the appropriate time for screening in premature and term neonates and there are different viewpoints in treating hypothyroidism in prematurity. According to the probable exceptions in this issue, there is no definite guideline. Therefore, regarding this confusion, this guideline aimed to help clinicians for rapid on-time decision making.http://ijpm.mui.ac.ir/index.php/ijpm/article/view/2535http://ijpm.mui.ac.ir/index.php/ijpm/article/download/2535/717718375