Abstract: Objective:This study was conducted to evaluate the roles of internal mammary sentinel lymph node biopsy (IM-SL -NB) in the treatment of breast cancer patients with clinically positive axillary lymph nodes.Methods:This study is a one-armed clini -cal research conducted from June 2013to October 2014. A total of 64breast cancer patients from Shandong Cancer Hospital with clini-cally positive axillary lymph nodes were enrolled in the study. All patients underwent axillary lymph node dissection. Meanwhile, IM-SLNB was performed in all patients using the new injection method of radiotracer. Results:Among the 64enrolled patients, the visual ization rate of internal mammary lymph node was 59.4% (38/64). For the 38patients who were subjected to visualization of the internal mammary node, the detection rate was 100% (38/38), and the incidence of complications was 7.9% (3/38). The metastasis rate of inter -nal mammary lymph node was 21.1% (8/38). Patients with upper inner quadrant tumors and metastasis of more axillary lymph nodes had a significantly higher chance of developing sentinel lymph node metastasis ( P<0.001 and P=0.017, respectively) than the other pa -tients. The clinical benefit rate of the above mentioned treatment was 59.4%. Among the patients,12.5% (8/64) received extra internal mammary radiotherapy, whereas46.9% (30/64) patients avoided the unnecessary internal mammary radiotherapy. Conclusion:IM-SL -NB should be performed in breast cancer patients with clinically positive axillary lymph nodes because IM-SLNB could provide the ac-curate indication of radiation to the internal mammary area, especially for the patients with upper inner quadrant tumors and those with a suspiciously high level of axillary lymph node metastasis.