A 49-year-old white man experienced maxillary sinus osteitis after removal of a portion of the maxilla containing root tips from a previous molar tooth extraction. After the patient had received long-term antibiotic therapy for that infection, a yeast-like organism was observed on smears from the patient's left nasal passage and its surgically enlarged communication with the maxillary sinus. The fungus has appeared on all subsequent smears, but early attempts to culture the organism were unsuccessful. A lipophilic yeast-like fungus, morphologically similar to the organisms seen on the direct smears and consistent with the genus Pityrosporum, was isolated in culture at this facility. Electron microscopy of the organism revealed cellular morphologic features believed to be unique to the Pityrosporum genus, thereby confirming the identity of the isolate as a member of that genus.