Background: Hearing loss (HL) is one of the most common disorders worldwide. Each year in Vietnam, 15,000-20,000 babies are born with congenital HL. Deafness is influenced by both genetic and environmental factors. Alterations in prominent deafness-related genes, GJB2, GJB6 and mitochondrial (mt) DNA 12S rRNA are thought to be the major causes of HL. Objective: In our study, mutational analysis of these genes were examined to determine the prevalence of gene mutations in Vietnamese non-syndromic deaf children. Materials and methods: Molecular analysis of these genes was investigated by PCR amplification and direct DNA sequencing. In this study, seventy six congenital deaf children and seventy eight healthy individuals with the well-characterized clinical profiles were enrolled. Result: There were four kinds of nucleotide changes in the GJB2 gene, including a pathogenic 235delC mutation that was identified in only patients with HL. Three known benign variants in the GJB2 gene were found. No mutations in GJB6 were observed. In the 12S rRNA gene, there were seven nucleotide alterations, with the m.1438A>G variant being detected in 100% all of the subjects in both patient and healthy control groups. Conclusion: Our study shows that the pathogenic 235delC mutation in GJB2 can be considered as a good candidate for further study on its functional analysis to address whether it contributes to the pathogenesis of HL in the Vietnamese population.