Breast cancer is the most common malignancy and the leading cause of death due to cancer in European women. Mammography screening programs aimed to increase the detection of early cancer stages were implemented in numerous European countries. Recent data show a decrease in mortality due to breast cancer in many countries, particularly among young women. At the same time, the number of sentinel node biopsy procedures and breast-conserving surgeries has increased. Intraoperative sentinel lymph node biopsy preceded by lymphoscintigraphy is used in breast cancer patients with no clinical signs of lymph node metastasis. Due to the limited sensitivity and specificity of physical examination in detecting metastatic lesions, developing an appropriate diagnostic algorithm for the preoperative assessment of axillary lymph nodes seems to be a challenge. The importance of ultrasound in patient qualification for sentinel lymph-node biopsy has been discussed in a number of works. Furthermore, different lymphoscintigraphy protocols have been compared in the literature. The usefulness of novel radiopharmaceuticals as well as the methods of image acquisition in sentinel lymph node diagnostics have also been assessed. The aim of this article is to present, basing on current guidelines, literature data as well as our own experience, the diagnostic possibilities of axillary lymph node ultrasound in patient qualification for an appropriate treatment as well as the role of lymphoscintigraphy in sentinel lymph node biopsy.