Background/aim: This study aimed to evaluate the facial nerve (FN) and internal auditory canal (IAC) on three-dimensional fast imaging employing steady-state acquisition (3D-FIESTA) magnetic resonance imaging (MRI) to define possible structural differences in cases of Bell's palsy (BP). Materials and methods: Fifty-six patients presenting with BP were included in this study. The measurements of the diameters and the cross-sectional areas (CSAs) of the FNs and IACs obtained on 3D-FIESTA MRI both on the affected and unaffected sides of all patients were compared. Results: A significant difference was found between affected and unaffected sides of the patients in terms of the mean CSA of the FN and IAC (P < 0.001). The CSAs of the FN were larger and the CSAs of the IAC were smaller on the affected sides than the equivalents on the unaffected sides of the patients, respectively. The difference in terms of the ratios of IAC CSA to FN CSA between affected and unaffected sides of the patients was also found to be statistically significant (P < 0.001). Conclusion: We have found that FN and IAC size differ on the affected sides of patients with BP. These anatomical differences may contribute to the risk for this disease.