To study the role of Haller's cell in the pathogenesis of chronic sinusitis, CT findings examined prior to endoscopic sinus surgery of patients with chronic sinusitis were investigated. Of 51 cases, Hailer's cell was present in 19 unilaterally or bilaterally. No significant correlation was found between the presence of Hailer's cell and the severity of a pathological shadow in the maxillary, anterior ethmoid, or frontal sinuses. However, in 13 cases of unilateral Hailer's cell, the pathological findings were significantly more severe in maxillary sinuses with Hailer's cell than in the oposite side without Hailer's cell (p<0.01). These findings suggest that Hailer's cell might be one of the important factors associated with the pathology of ostiomeatal complex as well as the pathogenesis of chronic inflammation in maxillary sinuses.