Objective:To study interpectoral nodes metastasis rate in breast cancer and its clinical significance.Methods:171 female patients undergone surgery for breast cancer were reviewed,of whom the interpectoral nodes were SUbjected to pathological examination.Results:Interpectoral nodes were identified in 25.7% of the 171 female patients,and the interpectoral nodes metastasis rate was 9.9%.The patients with interpectoral nodes metastasis had larger tumor size,later TNM classification,higher axillary apical nodes metastasis rate and lower ER positive rate.Conclusion:Dissection of interpectoral nodes should be regard as routine clinical practice in modified radical mastectomy,and interpectoral nodes should be snbjected to pathological examination.