The expression and distribution of signal transducer and activator of transcription 3 (STAT3), phosphorylated STAT3 (p-STAT3), and vascular endothelial growth factor (VEGF), as well as eosinophil infiltration in nasal polyps was detected to examine their roles and correlations in the nasal polyp pathogenesis. Using the streptavidin-biotin-peroxidase (SP) method, immunohistochemistry was performed on conventional paraffin sections of 30 surgery-resected polypous specimens and 10 inferior turbinate tissues that were resected during nasal septum deflection correction to detect the expression of STAT3, p-STAT3, and VEGF, as well as eosinophil infiltration. The rates of STAT3-, p-STAT3-, and VEGF-positive expression in the mucosal epithelium and glands of nasal polyps were 66.67, 56.67, and 76.67 %, respectively, values that were significantly higher than those in the inferior turbinate group. The number of eosinophils in the nasal polyps was significantly higher than in the inferior turbinate group. Expression of p-STAT3 and VEGF in nasal polyps and eosinophil infiltration was increased significantly and positively correlated, indicating that VEGF and eosinophil infiltration might be regulated by p-STAT3. Therefore, the expression of STAT3, p-STAT3, and VEGF, and eosinophil infiltration might be important factors in nasal polyp pathogenesis.