Most necrotizing (malignant) external otitis (NEO) occurs in diabetic patients and is commonly caused by Pseudomonas aeruginosa. We report an acquired immunodeficiency syndrome (AIDS) patient with NEO caused by Aspergillus fumigatus in which computed tomography (CT) showed destructive petrous bone involvement and magnetic resonance imaging (MRI) of the ear discovered extensive soft tissue and facial nerve involvement. Dedicated MRI studies of the ear in this type of pathology provide new insights relating to nerve dysfunction, that cannot be obtained with CT.