Schizophyllum commune, a basidiomycetous fungus, rarely causes disease in humans. We report a rare case of allergic fungal sinusitis caused by S. commune in a 14-yr-old girl. The patient presented with nasal obstruction and a purulent nasal discharge. Materials obtained during endoscopic surgery of the frontal recess revealed allergic mucin and a few fungal hyphae. A potato dextrose agar (PDA) culture from the allergic mucin yielded a rapidly growing white woolly mold. Although no distinctive features including hyphae bearing spicules or a clamp connection were present, the case isolate disclosed compatible mycological features including growth at 37degrees C, susceptibility to cycloheximide, and production of a tart and disagreeable smell. S. commune was confirmed by sequence analysis of the internal transcribed spacer region and D1/D2 regions of the 26S ribosomal DNA. We believe this is the first report of allergic fungal sinusitis caused by S. commune in Korea. Moreover, this report highlights the value of gene sequencing as an identification tool for non-sporulating isolates of S. commune.