The aim of this study was to compare ultrasonography with video-otoscopy for the evalution of the external ear canal and the tympanum. Fifty dogs with clinical signs ot the bilateral ear diseases were examined using otoscopy under general anesthesia. Ultrasonographic examination was performed with an 11 MHz linear-arrary probe and a 6.5MHz convex probe, with the external ear canal filled with saline. Saline functioned as a contrast media and enhanced image quality of ultrasonography. The images of 100 ears before and after the ear cleansing were obtained at otoscopy and ultrasonography. On the video-otoscopic images, the tympanic membrane was identified in 59 ears before the ear cleansing and 91 ears after cleansing. On the ultrasonography, the tympanic membrane was detected in 98 ears before the ear cleansing and in all ears after cleansing. With these results, it was concluded that ultrasonography with infusing saline into the ear canal, could be a useful diagnostic procedure to identify the tympanic membrane in otitis dogs.