Small cell carcinoma commonly breaks out in the lung and only about 4% of the small cell carcinoma arises in the extrapulmonary sites. In the head and neck lesion, small cell carcinoma of the sinonasal tract is extremely rare, and only 2 cases of Korean literature of primary small cell carcinoma have been reported ; the one is on nasal cavity, and the another is on nasal septum. Recently we have experienced a case of a 76-year-old male patient of small cell carcinoma arising in maxillary sinus with coexisting fungal ball lesion. And the systemic radiologic study showed no evidence of primary lung lesion. So we report this case with a review of literature.