Auditory brainstem response (ABR) was used to detect the preva­lence of hearing loss among 2-4 mo­nths old thirty infants with early treat­ed congenital hypothyroidism (CH), diagnosed during the screening pro­gram. It was also used to correlate such prevalence to the severity of the disease at time of diagnosis as well as the time of starting treatment. Bilat­eral mild to moderate and unilateral mild hearing losses were found in 5 and 2 CH infants respectively. When the thirty infants with CH were com­pared to 12 controls as regards differ­ent ABR variants, wave I absolute la­tency was found to be significantly prolonged in CH group, while l-lll, tll-V and i-V inter-peak latencies were significantly shorter than norms. Moreover, wave V threshold was significantly higher in CH group than that of norms. CH infants were divided into severe and less severe subgroups {based on the pre-treatment level of FT4) and only wave V absolute laten­cy was found to be significantly short­er in the severe subgroup. No signifi­cant correlation was found between pre-treatment level of FT4 and differ­ent ABR variants except for wave V absolute latency (positive correlation). CH infants were also subdivided into late and early onset treatment sub­groups (based on the age at which treatment with Na-L-thyroxine started) and only V/l amplitude ratio was sig­nificantly higher in early onset treat­ment subgroup. There was a signifi­cant negative correlation between age at which treatment started and V/l amplitude ratio. It can be concluded that children with CH