Background: A narrow internal auditory canal (IAC) is significantly associated with congenital sensorineural hearing loss. It would therefore seem likely that any patient with an IAC measured radiographically to be under the normal range represents an abnormality and probable IAC stenosis. If narrow IAC is diagnosed with routine magnetic resonance imaging (MRI), then the cochlear nerve may be evaluated with special MRI studies. However, there is no consensus in the literature on the normal measurements of the IAC or on what parameters should be used to determine narrow IAC using MRI. In this study, we aimed to assess the normative size of IAC in normal-hearing ears and to determine whether canal size varies with age and gender using MRI.