Objectives: This research aims to study computerized tomographic imaging features of concha bullosa and the relationship between concha bullosa and chronic rhinosinusitis. Patients and method: The research carried out on 104 patients having clinical symptoms of chronic rhinosinusitis and being defined to have concha bullosa on CT scan, by cross sectional descriptive study, from June 2011 to July 2012. Result: Patients with unilateral concha bullosa (CB) were 49/104 cases (45.2 percent), with bilateral CB were 55/104 cases (52.8 percent). Main functional symptoms of chronic rhinosinusitis appeared with high rate. There was a statistically significant relationship between concha bullosa and chronic sinusitis on CT scan: among nasal fossae having no concha bullosa, no sinusitis occupied 32.7 percent (16/49), sinusitis occupied 67.3 percent (33/49)
among nasal fossae having concha bullosa, no sinusitis occupied 16.4 percent (26/159), sinusitis occupied 83.6 percent (133/159). There was a statistically significant relationship between transverse diameter and anterior-posterior diameter of concha bullosa with chronic sinusitis on CT scan: nasal fossae having concha bullosa with transverse diameter 4mm or anterior-posterior diameter 8mm had higher risk of sinusitis. Conclusion: the authors found the relationship between diameter of concha bullosa and chronic sinusitis, the bigger the concha bullosa, the higher the prevalence of chronic rhinosinusitis.