The frequency of concha bullosa, paradoxical middle turbinate, and septal deviation on coronal computed tomographic scans evaluating sinus disease is known, but the incidence in normal subjects is unknown. We compared 100 consecutive scans performed for evaluation of sinus disease with 82 consecutive scans performed for evaluation of orbital pathology. Patients with sinus disease had significantly more frequent findings of disease in the osteomeatal complex and all sinuses. Concha bullosa was more common in patients with sinus disease (p less than 0.05), as was septal deviation (p less than 0.01). Paradoxical turbinate was equally common. Concha bullosa was associated with anterior ethmoid disease (p less than 0.04). Septal deviation was associated with osteomeatal complex disease (p less than 0.01) and with anterior (p less than 0.04) and posterior (p less than 0.04) ethmoid disease. Paradoxical turbinate was not associated with sinus abnormalities. These data imply a possible causal relationship between concha bullosa or septal deviation and sinus disease.