The Aspergillus sinusitis is relatively rare and mainly develops in immunocompromised hosts, but it sporadically appears in the immunocompetent patients, where its incidence tends to be increasing. Because the clinical features of this disease are similar to those of chronic suppurative sinusitis, this entity may be overlooked. Six cases of aspergillus sinusitis seen from January 1990 to August 1992 were analyzed on their clinical features and laboratory findings, focusing on the possibility of preoperative diagnosis. 1) The mean age was 52 years old (from 45 to 59 years old). 2) No case had the operative history and two cases suffered from diabetes mellitus. 3) All cases complained of nasal obstruction and hyperrhinorrhea. Physical examination showed the mucopurulent discharge in the nasal cavity (6 cases) and the nasal polyp (3 cases), and cheek tenderness (2 cases), in all cases? 4) The characteristic computerized tomographic (CT) findings were hyperattenuated lesions in the maxillary sinus and the in nasal cavity near the natural ostium. 5) Gross specimen revealed a fungus ball containing a semisolid, brownish, material with a chees-like consistency. As soon Microscopically, there were many small septated hyphae branching at a 45-degree angle. 6) Five cases underwent the Caldwell-Luc operation with intranasal ethmoidectomy, while one case underaent the intranasal ethmoidectomy with middle meatal antrostomy. In no case were antifungal agents administered systemically.