Aim: To investigate the frequency of an Asian founder mutation c.100C>T (p.R34X) that dominates the TMC1 gene mutation spectrum, in a large cohort of prelingual hearing impaired (HI) from south India. Methods: A total of 360 children from deaf schools and 116 prelingual adult HI from assortative mating cohort were included in the study, after excluding for the common GJB2 etiology. We determined the genotype of the probands using PCR-RFLP (polymerase chain reaction-restriction fragment length polymorphism) method. Results and discussion: p.R34X mutation was not found in all the 476 hearing impaired screened in our cohort unlike other studies who reported low prevalence of TMC1. Conclusion: We conclude that c.100C>T mutation is not a significant cause of deafness in the south Indian population. However the actual frequency of TMC1 gene mutations contributing to deafness, can be obtained only by sequencing all the 24 exons of the gene.