An association between thyroid hormone and auditory function has long been recognized in patients with congenital hypothyroidism (CH). Research with laboratory animals has demonstrated that thyroid hormone plays a significant role in the maturation of inner ear structure. This study was conducted on 109 CH patients who were diagnosed by neonatal screening and treated early, for whom Transient Evoked Otoacoustic Emissions (TEOEs) and Auditory Brainstem Evoked Response (ABR) were performed to demonstrate the effect of CH on hearing. Results: there was no hearing loss detected in the study group, ABR showed significant prolongation of wave I latency in the cases, there was no statistical significant difference between early and late treatment group. There was no statistical significant difference between high and low treatment dose group except for TEOEs parameters, which were higher in the high treatment dose group. Conclusion: children with CH treated early in life with replacement L-thyroxine demonstrate no hearing loss with better hearing results and IQ in children with high dose. Neonatal thyroid screening is advocated for all children and should be done as soon as possible after birth. High dose L-thyroxine (15ug/kg/d) is advocated to ensure the best possible outcome.