Hearing loss is the most common sensory deficit in humans. Early diagnosis and intervention are important in the acquisition of hearing, speech, and linguistic skills, thereby contributing to the positive development of the child. Aims:To study the state of hearing in children living in Kazakhstan, to identify the proportion of mutations in the connexin-26 gene in the event of sensorineural deafness.Methods: prospective case-control analysis. In total, 454 participants were examined.Results: It has been identified that for the Kazakh population with regard to the polymorphism of gene frequency GJB2 (35delG, 235Cdel, 167delT) the most characteristic is allele spectrum frequencies of 167delT polymorphism. Conclusion:Thus, the population frequencies of the mutation were studied: 35delG (0.49±0.28), 235delC (0.66±0.33), 167delT (1.64±0.51) of the GJB2 gene in the Kazakh population, which makes a significant contribution to the study of the gene pool of Kazakhs.