With the advent of functional endoscopic sinus surgery, coronal plane computed tomography (CT) of paranasal sinus was the essential part of nasal surgery to evaluate bony anatomic variation and mucosal abnormalities of paranasal sinuses. In this study, the coronal plane CT scans of 118 patients with nasal polyposis were reviewed to analyze the mucosal abnormalities and the bony anatomic variations. Especially in bony anatomic variation study, we compared the result with coronal CT of 70 non-sinusitis patients. In nasal poluposis, mucosal abnormalites were detected in the following frequencies : anterior ethmoid sinus(97.7%), maxillary sinus(77.6%), frontal sinus(62.6%), posterior ethmoid sinus(50.5%), sphenoid sinus(40.8%). And we compared bony anatomic variation such as, Haller's cell, pneumatization of middle turbinate, paradoxical curvature of middle turbinate, agger nasi cell, hypoplastic maxillary sinus and septal deviation. There was no statistical difference between the two groups(p>0.05). The authors conclude that the mucosal abnormality of the nasal polyposis was most frequently involve in anterior ethmoid sinus and there was no clinnical significance of bony anatomic variations in forming nasal polyposis.