Although exposure to Aspergillus, a cosmopolitan and ubiquitous fungus in nature, is common, otomastoiditis is exceedingly rare. However, immunosuppression is a major predisposing factor for opportunistic Aspergillus infections. We report the case of a Hispanic man with acquired immunodeficiency syndrome and a low CD4+ T-cell count (21/mm3) who presented with Aspergillus otomastoiditis complicated by peripheral facial nerve palsy 2 weeks after initiation of antiretroviral therapy. The patient had complained of a left earache 3 weeks prior that resolved quickly with antibacterial therapy. Cases of Aspergillus ear infections in patients with acquired immunodeficiency syndrome before the advent of highly active antiretroviral therapy have been reported. As the patient's human immunodeficiency virus viral load became undetectable rapidly, it is possible that antiretroviral therapy could have exacerbated the infection leading to its final diagnosis.