A fulminating infection of the nose, sinuses, orbits, and cranial structures may be caused by a fungus of the Mucorales order, and may closely resemble acute sinusitis of bacterial or viral origin. The disease has occurred with increasing frequency in the past 10 years and will undoubtedly become more important with wider use of antibiotics, corticosteroids, and other chemotherapeutic agents. Certain fungi are remarkable in their ability to produce disease in the absence of underlying illness (blastomycosis, coccidioidomycosis, etc.), while others usually complicate a preexisting infection (Monilia, Aspergillus, etc.).27 Most of the diseases they produce are nonfatal, but two notable exceptions are blastomycosis and mucormycosis. Either of these infections may prove fatal, but of the two mucormycosis is more serious, sometimes killing the patient in a matter of days. The causative organism becomes invasive and nearly always lethal in patients being treated with chemical agents such as corticosteroids, antileukemic