Objectives/Hypothesis: Over half of chronic rhinosinusitis with nasal polyps (CRSwNP) patients in China show noneosinophilic inflammation. The aim of this study was to compare the clinical characteristics of eosinophilic and noneosinophilic CRSwNP and to identify the predictors of eosinophilic CRSwNP. Study Design: A retrospective study. Methods: There were 155 CRSwNP patients enrolled in the Tongji cohort. Eosinophilic CRSwNP was diagnosed according to our previously published histologic criterion. The demographic and clinical features were compared between eosinophilic and noneosinophilic CRSwNP. Factors associated with eosinophilic CRSwNP were determined with regression analysis, and optimal cutoff points of the predictors were determined by a receiver operating characteristic curve. The optimal cutoff points of the predictors were validated in an independent group of 35 CRSwNP patients referred to as the Taizhou cohort. Results: A male preponderance, a higher prevalence of smoking and atopy, and higher peripheral blood eosinophil absolute count and percentage and blood IgE levels were found in eosinophilic CRSwNP compared with noneosinophilic CRSwNP. Peripheral eosinophil absolute count and percentage were independently and significantly associated with eosinophilic CRSwNP. An absolute blood eosinophil count >= 0.215 x 10(9)/L yielded a sensitivity of 74.2% and a specificity of 86.5%, and a blood eosinophil percentage >= 3.05% yielded a sensitivity of 80.3% and a specificity of 75.3% for the diagnosis of eosinophilic CRSwNP in the Tongji cohort. The validation study in the Taizhou cohort revealed a lower sensitivity and specificity. Conclusions: Eosinophilic and noneosinophilic CRSwNP displayed significant differences in certain clinical features. Peripheral blood eosinophil count could distinguish eosinophilic and noneosinophilic CRSwNP in Chinese adults.