The diagnostic value of a contrast enhanced MRI in patients with Bell's palsy was investigated. It was a characteristic finding that the internal acoustic meatal segment of the facial nerve was enhanced only on the affected side. The signal intensity ratio of the geniculate ganglion and the tympanic segment was significantly higher on the affected side than on the normal side. The severity of the facial palsy and the results of physiological examinations showed no relation to the results of MRI scans. Gd enhanced MRI thus appears to provide some useful findings for estimating the affected region of Bell's palsy, whereas it is not considered to be valuable in the diagnosis of severity.