Abstract: Objective To explore the expression of neuropilin-1 (NRP-1) in triple negative breast cancer and its correlation with clinicopathologic features. Methods A total of 69 triple negative breast cancer patients and 30 patients with benign breast lesions were included into the current study. Their clinical data were retrospectively analyzed, while their pathological specimens were prepared into tissue samples. The expression of NRP-1 was detected by immunohistochemistry in triple negative breast cancer and breast benign lesions. Meanwhile, the relationship between NRP-1 expression and the patients’ clinicopathological features was analyzed. Results The positive expression rate of NRP-1 was significantly higher in triple negative breast cancer than those in breast fibroadenoma and breast cystic hyperplasia (P=0.000). There was no significant difference as to the expression of NRP-1 between fibroadenoma and breast cystic hyperplasia (P=0.6767). The expression rate of NRP-1 was gradually increased as the stage of triple negative breast cancer was elevated after surgery (P=0.000). For triple negative breast cancer patients, those with axillary lymph node metastasis showed a high expression rate of NRP-1 than those without lymph node metastasis (P=0.001). The expression of NRP-1 in triple negative breast cancer patients was associated with tumor size, cell differentiation, pTNM stage and recurrence or distant metastasis in triple negative breast cancer. Conclusions NRP-1 over-expression may be closely associated with the pathogenesis and axillary lymph node metastasis of triple negative breast cancer, and may become a new target for the treatment of the cancer.