In combination with psychophysical testing and electrophysiological studies, magnetic resonance imaging plays a role in the clinical evaluation of patients with an olfactory dysfunction. Quantitative measurements of olfactory bulb volume and of olfactory sulcus depth, and the morphological depiction of structural abnormalities, make synergistic contributions to the accurate radiological diagnosis of smell dysfunction. Moreover, the plasticity of our olfactory system can be demonstrated by temporal changes in OB volumetric measurements. In this paper, we provide an outline of how to measure olfactory bulb volume and olfactory sulcus depth, with numerous illustrative cases of patients with congenital anosmia, post-infectious or posttraumatic olfactory loss and sinonasal-related olfactory dysfunction.