Background/Aim. Chronic sinusitis is a disease characterized with mucosal inflammatoion of nasal and paranasal sinuses for at least 12 weeks. In order to assess the extent and severity of inflammatory changes in paranasal sinuses CT score according to Lund-Mackay is the most commonly used. Recent studies show the possibility of existing different subtipes of chronic rhinosinusitis, pointing out the presence of nasal polyps and their influence on the severity of chronic rhinosinusitis. The aim of this research was to examine the influence of sinonasal polyposis on the extensity of inflammatory changes on computerized tomography (CT), evaluated by the Lund-Mackay CT score. Methods. A prospective study compared the Lund-Mackay CT score values between the patients with chronic rhinosinusitis associated with nasal polyps and those without them. We determined mean values of the total CT score in both groups of the patients, as well as mean values of CT score for each group of sinuses and ostiomeatal complexes. Results. The study included 90 patients, 47 males and 43 females, 45-year old on average, diagnosed with chronic rhinosinusitis on the basis of diagnostic algorithm. The group with uncomplicated chronic rhinosinusitis (without nasal polyps) consisted of 30 patients and the group with complicated chronic rhinosinusitis (with nasal polyps) of 60 patients. Observing these two groups of patients revealed statistically highly important intergroup difference in CT score for each group of sinuses and ostiomeatal complexes. The mean value of total CT score in the group with uncomplicated chronic rhinosinusitis was 4.37 while in the group with complicated chronic rhinosinusitis it was 16.05 (p < 0.01). Conclusion. Chronic rhinosinusitis complicated by sinonasal polyposis is characterized with more extensive inflammatory changes on CT and, consequently, with higher CT score for each group of sinuses and ostiomeatal complexes, as well as higher total CT score.