Image-guided minimally invasive needle biopsy is an established method in the diagnosis of breast cancer, which - when indicated correctly and carried out with quality control - equals or even surpasses open diagnostic surgery. Therefore, an open diagnostic biopsy should only be performed as well-founded exception. Depending on the visibility in the various diagnostic techniques of the condition to be clarified histologically, needle biopsy has to be carried out with the image-guided procedure which can identify the mammary lesion most reliably. If a lesion is detectable mammographically as well as sonographically, a high-speed large-core biopsy is preferred, taking the strain on the patient and the costs into account, too. In the case of suspect microcalcifications, the needle biopsy has to be controlled stereotactically. Here, vacuum-assisted procedures [Mammotome, VacuFlash (BIP)/Vacora (Bard)] yield markedly better results when compared with large-core biopsy and are also preferred for lesions which are only visible on magnetic resonance tomography. Without exception, preoperative wire marking should be used in cases of suspect nonpalpable lesions in imaging diagnostics or even more so of lesions which have already been classified histologically as malignant by minimally invasive procedures before surgery. This is the only way to safely find the suspect and nonpalpable lesion during the operation and to excise it with a sufficient safety margin while preserving as much healthy issue as possible. Quality-controlled diagnostics and therapy of breast cancer constitute an interdisciplinary challenge and yield optimal results only when all concerned specialties collaborate in the best possible way.