The authors examined 105 proved cases of aspergillosis involving the paranasal sinuses or nasal fossa. Mycosis was always unilateral, and the maxillary sinus was infected in all cases. Early stages were manifested by an intraluminal soft-tissue mass representing the mass of mycelia. Fifty-nine patients (56%) demonstrated very dense intraluminal calcifications. Such dense concretions suggest the diagnosis of aspergillosis.