Congenital hypothyroidism (CH), a condition where the thyroid gland hormone synthesis is affected, potentially leading to preventable mental retardation. It outlines the screening process for CH in newborns, the historical background of screening programs, different testing methods, and the implications of test results. Additionally, it covers treatment strategies and considerations for managing CH. CH occurs at a frequency of 1:2000-1:4000 in newborns and can have permanent or temporary causes. Diagnosis typically occurs after three months, but early detection is crucial to prevent irreversible neurological effects. Screening programs aim to identify affected infants promptly, although challenges like false positives and negatives exist. Various testing methods, including primary TSH, primary T4, and combined T4 and TSH screening, are employed, each with its advantages and limitations. False-positive and false-negative results can occur due to factors like sampling time and test cut-off values. The text also discusses the CH screening program in a specific country, detailing the screening process and recall criteria. It emphasizes the importance of considering hypothyroidism in newborns with clinical symptoms, regardless of screening results, to prevent adverse neurodevelopmental outcomes. In conclusion, early detection and treatment of CH are crucial for preventing long-term complications. Screening programs play a vital role in identifying affected infants, but clinical evaluation remains essential for cases with suspicious symptoms. Effective management requires a comprehensive approach, including accurate testing, appropriate treatment, and regular monitoring.