A retrospective radiographic study was performed on 142 proven cases of Aspergillosis in the paranasal sinuses. In all but two cases the mycosis was unilateral and in all cases the maxillary sinus was infected. A common radiographic presentation was a homogeneous opacity of the infected maxillary sinus, while about 50% of the cases showed nonspecific infectious changes of other paranasal sinuses additionally. Earlier stages of the disease showed an intraluminal soft tissue mass, representing the mycelium conglomerate. Bone destruction due to Aspergillosis could not be proven. 58% of the cases presented with intraluminal structures of metallic density. Histochemical studies proved these to consist mainly of tertiary Calciumphosphate. These concrements are considered to be pathognomonic of Aspergillosis.