We herein report a case of second sentinel lymph node biopsy (SLNB). A 57-year-old woman underwent breast-conserving surgery including axillary clearance at Aichi Cancer Center on October 20, 2003. Recurrent tumor in the conserved breast was diagnosed in March 2006. She received SLNB using radioactive tracer. Preoperative lymphoscintigraphy detected 2 parasternal lymph nodes as hot spots. No abnormal lymph nodes were revealed on preoperative computed tomography. Salvage mastectomy was performed along with dissection of the Rotter and infraclavicular lymph nodes and biopsy of the detected parasternal lymph nodes. Micrometastases were discovered in both parasternal lymph nodes detected as sentinel lymph nodes. No more metastases were seen in the other lymph nodes. Reoperative SLNB offers the possibility of detecting metastasis in residual lymph nodes and determining whether chemotherapy should be used.