The promising results of various studies applying different methods of SN biopsy in heterogeneous patient subpopulations, show that sentinel lymph node biopsy is a reliable and minimally invasive method for the determination of the nodal status in breast cancer patients. While multicenter studies for the evaluation of the method's accuracy are still ongoing, future indications and contraindications are discussed. Based on our own experience, we try to give an actual overview of the potentials and problems of sentinel node biopsy in breast cancer. Sentinel node detection was performed in 146 patients with breast cancer stages I-III, consisting of 127pT1/2 tumors and 19pT3/4. All of them underwent standard axillary dissection after SN biopsy. Using the radionuclide method including preoperative lymphoscintigraphy and intraoperative gamma. Probe detection, the detection rate varied in relation to the tumor size between 94% for tumors with a diameter < 1 cm, 85% (1-3 cm), 70% (3-5 cm) and 63% (> 5 cm). The accuracy of the SN-biopsy in the prediction of the nodal status varied also with tumor diameter ranging from 100% for very small tumors (< 1 cm), over 97% (1-3 cm) and 88% (3-5 cm), to 67% (> 5 cm). In the subgroup of patients with pT1-2 tumors (n = 106), 57 patients (53%) showed true negative sentinel nodes, 38 (36%) revealed tumor cells in the H&E staining and an additional 7 patients (7%) solely in the immunohistochemical staining. 4 (4%) of these patients, all of them from the first half of the study period, underwent false-negative SN-biopsy, all of them showing lymphangiosis carcinomatosa and/or extensive infiltration of the metastatic lymph node(s). The results presented show, that in about 50% of early breast cancer patients surgical intervention could potentially be avoided after a negative SN-biopsy, and an additional 5-10% of conventionally nodal negative patients can be found by immunohistochemical examination of the sentinel node. The SN concept is not recommended in clinically nodal positive patients or advanced disease. Potential applications include the evaluation of parasternal lymph nodes and patients with recurrent tumor. Before clinical application, quality control of the medical center and the performing surgeon have to be established potentially including the performance of about 20 procedures under supervision for each surgeon, an individual accuracy of at least 93%, and the possibility of immunohistochemical staining as well as a regular follow-up.