Mycetomas of paranasal sinuses are more frequently diagnosed with the widespread use of nasal endoscopy and computed tomography (CT). We present a series of 109 cases treated by functional endoscopic sinus surgery (FESS) with a mean follow-up of 29 months. All localizations were seen, and contrary to what was initially thought, seven cases presented in multiple sites. Several clinical presentations were found, from a pansinusal involvement to a simple mycetoma hanging in a superior meatus. A heterogeneous sinus opacity with microcalcifications on CT scan is very suggestive of the diagnosis, but a homogeneous opacity may be encountered even with bone lysis. FESS was performed in all cases to obtain a wide opening of the affected sinuses, permitting a careful extraction of all fungal material. In the postoperative period, no medical treatment is prescribed. With a mean follow-up of 29 months, only four recurrences were seen. This study reinforces the interest in FESS for cases of mycetoma of the paranasal sinuses.