BACKGROUND Nasal polyposis is the benign protrusion of soft tissue into the nasal cavity, with multifactorial origin. This study is designed to examine the suggested role of IgE and CD4 and CD8 lymphocytes in the pathogenesis of nasal polyposis. METHODS Blood samples were taken from 32 patients with chronic polypoid sinusitis and 32 controls. CD4 and CD8 total lymphocyte count were determined by flow cytometry and the level of serum IgE was measured by ELISA. Nasal discharge samples were also collected for determining IgElevel in both patients and controls during surgery. RESULTS In 68.8% of patients a history of allergy was present. The level of nasal discharge IgE was significantly higher (p < 0.001) in patients compared to controls, but the difference between serum IgE levels was not significant (p > 0.05). CD8 concentration and blood lymphocytes were significantly higher (p < 0.001) in the patients group, while CD4 concentration was significantly lower (p < 0.001) in them. Finally, CD/CD8 ratio was significantly lower (p < 0.001) in the patients group. CONCLUSIONS This study suggests that a change in the amount of CD4 and CD8 lymphocytes and an increased level of local IgE contribute to nasal polyposis, but the results should be confirmed in more extensive studies including cytokine analyses. Such increasing insights in the pathophysiology of nasal polyposis open perspectives for new pharmacological treatment options, with immunologic factors as potential targets.