Magnetic resonance (MR) examinations of three patients with rhinocerebral mucormycosis are reviewed. The clinical course is outlined and the MR characteristics are analyzed in light of the known pathology. The major MR findings include sinus and orbital disease followed by deep facial extension. Involvement of basal portions of the hemispheres, brain stem, and hypothalamus occurred rapidly following ipsilateral facial or orbital invasion in all three cases. Regions of intracerebral inflammation were hyperintense compared with normal parenchyma on T2-weighted and proton density-weighted images. Septic cavernous sinus and internal carotid artery thrombosis was diagnosed by MR in one case. Magnetic resonance demonstrated partial resolution of intracerebral abnormalities that accompanied clinical improvement in the one surviving patient.