Objective To detect the expression of FOXP3 + TILs in primary invasive breast cancer analyze the correlation between the expression level of FOXP3 + TILs and the clinicopathological characteristics of breast cancer and explore the relationship between FOXP3 + TILs and the prognosis of breast cancer. Method Surgically resected samples from 156 patients with invasive breast cancer BC were assessed for the expression of FOXP3 + TILs and CD4 + TILs by immunohistochemistry. The correlation between FOXP3 + TILs and the patients ' clinicopathological characteristics was explored. Kaplan - Meier survival analysis and Cox proportional hazards regression model were used to assess the correlation between FOXP3 + TILs and breast cancer-specific survival and to stratify the evaluation of breast cancer subtypes. Result Elevated FOXP3 + TILs infiltration were significantly correlated with high histological grade P= 0. 021 positive human epidermal growth factor receptor-2 HER-2 P=0. 018 Progesterone receptor expression PR P=0. 016 high Ki-67 index P = 0. 042 and axillary lymph node metastases P = 0. 001 . There was no significant correlation between CD4 + TILs expression and the clinicopathological features of all patients. Tumors with concomitant high expressions of FOXP3 + TILs had worse overall survival OS and disease-free survival DFS 64. 7% vs 87. 6% χ 2 = 15. 3 P<0. 001 56. 9% vs 80. 0% χ 2 = 13. 1 P<0. 001 . The patients with axillary lymph node metastases with the high expressions of FOXP3 + TILs infiltration had worse DFS P<0. 001 . Multivariate analysis showed that FOXP3 + TILs was independent predictors of OS HR=2. 732 95%CI=1. 174~6. 207 P=0. 023 and DFS HR=2. 092 95%CI= 1. 068~4. 088 P = 0. 032 . Conclusion The high expression of FOXP3 + TILs in breast cancer is associated with tumor progression higher expression of FOXP3 + TILs indicates wores OS and DFS FOXP3 + TILs maybe a prognostic marker for breast cancer.