The fungus ball is a rare disease among the fungal infections of paranasal sinuses. This case was presented as our patient who was diagnosed as maxillary sinus fungus ball without history of health problems.

A 50 year-old woman, applied to the department of Ear Nose and Throat Surgery (Otorhinolaryngology) with the complaints of left nasal obstruction, post-nasal drainage and left-sided headache for two months. A mass was detected in left maxillary sinus by computed tomography and drainage was done by endoscopic sinus surgery. Microscopic examination revealed suspicious morphologic structure for Aspergillus species.

The fungus balls should be considered in the differential diagnosis and mycologic examination should be done, especially in the middle aged women with an unilateral mass in the nasal cavity, even the patient didn't have a history of an invasive orthodontic procedure, any chronic diseases and immunosuppressive drug usage.