Objective: To determine total inner ear fluid volume and cochlear and semicircular canal/vestibule volumes of a normal population to form a base for dimensional abnormalities of inner ear structures. Study Design: Cross-sectional. Setting: Academic otology and radiology practices. Patients: Twenty-nine healthy volunteers (13 male patients and 16 female patients with an average age of 31 yr) without any known history of intrauterine infection or any exposure to ototoxic agents and no abnormality at physical examination from the standpoint of hearing loss were included. Interventions: Twenty-nine volunteers underwent magnetic resonance imaging of the temporal region by means of thin-section T2-weighted sequences. The images were evaluated by the radiologist for the presence of any gross configurational abnormality. Fluid volume of each inner ear and components of labyrinth (cochlea, semicircular canals/vestibule) were calculated with the help of an online work station. Main Outcome Measure: To determine the volume of components of the labyrinth and total inner ear fluid, which may form a base for future studies about sensorineural hearing loss. Results: The volumes of total inner ear fluid, cochlea, and semicircular canals/vestibule were calculated. The mean and standard deviation of total inner ear fluid volume, cochlear volume, and semicircular canal/vestibule volume were obtained for each volunteer. Results were assessed with the help of statistical tests. Conclusion: There was no statistically significant difference between right and left inner ear fluid volumes of male and female subjects. There was also no statistical difference between right and left inner ear volumes when age and sex were not concerned. During evaluation of volumes according to sex, the difference between right and left inner ear fluid volumes was also assessed. Left semicircular canal/vestibule volume of female subjects were found to be higher than that of male subjects. The difference between right and left semicircular canal/vestibule volumes of female subjects was higher than the difference between right and left semicircular canal/vestibule volumes of male subjects. © 2005, Otology & Neurotology, Inc.