Allergic fungal sinusitis (AFS) is a noninvasive form of fungal rhinosinusitis resulting from an IgE-mediated hypersensitivity reaction. The diagnosis of AFS can be established by demonstrating type I hypersensitivity, presence of fungus in mucus, eosinophilic mucin, nasal polyposis, and characteristic CT scans. Although AFS is not unusual and its incidence may be increasing, few cases have been reported in Korea. Here, we report the first case of typical AFS in which Curvularia species was isolated by culture. (Korean J Clin Microbiol 2010;13:98-101)