Five cases of significant asymmetry of the internal auditory canals as a normal variant are reported; these were proven normal by iophendylate injection tomographic study. The incidence of significant asymmetry of the canals between the two sides is 2% in our series. Even when significant asymmetry in size and configuration of the internal auditory canals is present, a conclusive diagnosis cannot by made without the benefit of iophendylate injection cisternography. The technique of cisternography using a small amount of iophendylate injection (1 to 3 ml) combined with polytomography is described briefly.