Background: Analysis of recent research indicated that T-helper cells may play an important role in the pathogenesis of chronic rhinosinusitis (CRS) with nasal polyps (CRSwNP) and CRS without nasal polyps (CRSsNP). Objective: The purpose of this study was to investigate the peripheral blood Th1 and Th2 cells and eosinophil population in patients with CRS. Methods: Peripheral blood samples were obtained from nine nonatopic controls, 37 patients with CRSsNP, and 66 patients with CRSwNP. The samples were then analyzed by flow cytometry analysis (Th1 cell [CD4 (-), interleukin 4 (+), interferon gamma (-)1 ]; and Th2 cell [CD4(-), interleukin 4(+), interferon gamma (-)1]). The patients were stratified into four groups based on their allergic status by using skin-prick test results and immunoglobulin E level measurements as the following: (1) nonatopic CRSsNP, (2) nonatopic CRSwNP, (3) atopic CRSsNP, and (4) atopic CRSwNP. Eosinophil counts were also compared. The severity of nasal diseases in these patients was assessed via the Lund-Mackay score. Results: No significant differences in peripheral blood Th1 and Th2 cells were found among all the atopic, nonatopic CRS groups, and the nonatopic control groups. Peripheral blood eosinophil levels in atopic CRSwNP were significantly elevated compared with the nonatopic controls (p < 0.05), but no significant difference was found among all atopic and nonatopic CRS groups. Conclusion: Analysis of our data demonstrated that a proportion of systemic Th1-and Th2-skewed lymphocytes in all CRS groups were similar to that in healthy subjects, irrespective of atopic status. The patients with CRSwNP and with atopy but not the patients with CRSsNP and with atopy demonstrated systemic eosinophilic inflammation. Further studies are needed to investigate underlying pathophysiologic mechanism or endotypes.