PURPOSE: To assess the safety and potential equivalence of the use of hemosiderin compared to the Technetium-99 in sentinel lymph node biopsy in human breast cancer. METHODS: Non-random sample of 14 volunteer women diagnosed with breast cancer with primary tumors (T1/T2) and clinically tumor-free axilla were submitted to the identification of sentinel lymph node using hemosiderin obtained from autologous blood injected in the periareolar region 24h before surgery on an outpatient basis. Patients received preoperative subareolar intradermal injection of Technetium-99 in the immediate preoperative period. Patients were submitted to sentinel lymph node biopsy, with incision in the axillary fold guided by Gamma-Probe, dissection by planes until the identification of the point of maximum uptake of Technetium-99, identifying the marked nodes and their colors. All surgical specimens were sent for pathological and immunohistochemical study. RESULTS: The results showed no evidence of side effects and/or allergic and non-allergic reactions in patients submitted to SLNB with hemosiderin. The SLN identification rate per patient was 100%. SLNB identification rate per patient with hemosiderin was the same as that of Technetium, with a concordance rate of 100% between the methods. CONCLUSION: Hemosiderin is a safe dye that is equivalent to Technetium in breast sentinel lymph node biopsy.