We have established an experimental model of fungal sinusitis in rabbits to analyze the chronology and the pathogenesis of the development of noninvasive fungal sinusitis due to Aspergillus fumigatus. Thirty-four Pasteurella-free New Zealand white rabbits divided into three groups were included in this study. In the first group (10 rabbits), A fumigatus was inoculated into the maxillary sinus. In the second group (10 rabbits), A fumigatus was inoculated into the maxillary sinus in the presence of a wound in the mucosa. In the third group (14 rabbits), A fumigatus was inoculated into the maxillary sinus in the presence of a blocked ostium. On days 15 and 30, endoscopic, histopathologic, bacterial, and mycological examinations of both maxillary cavities and mucous membrane were performed. The rabbits were painlessly sacrificed 30 days after inoculation; mucosal and bone biopsies of the maxillary sinus cavities were performed for histopathologic studies. We found that noninvasive fungal sinusitis had been induced in 2 rabbits of the second group and 8 rabbits of the third group. We conclude that introduction of fungi into a sinus with a blocked ostium induces fungal sinusitis. The present model of experimental fungal sinusitis seems to be reproducible and suitable for further studies of the development of fungal sinusitis.