Hearing loss (HL) is the most common sensory defect. Various genetic as well as environmental factors have been shown to contribute in it. More than 100 loci have been recognized to cause autosomal recessive nonsyndromic hearing loss (ARNSHL). Here, we report a 6-year old female patient with bilateral pre-lingual HL in whom a mutation has been identified in TRIOBP gene (c.6362C>T, S2121L). In silico analysis has shown that this variant is possibly pathogenic. Although several mutations have been detected in this gene in various populations, this is the first report identifying TRIOBP mutation in Iranian population. Consequently, the results of the present study may be of importance in genetic counseling.