The widespread use of mammography in breast cancer screening has increased the number of non-palpable breast lesions being detected in which the differential diagnosis between benign and malignant cases requires surgical biopsy. In order to remove these mammographically identified lesions the surgeon must be guided, which is why the techniques guiding the surgeon during lesions ablation have become most important. Accurate preoperative lesion localization must be done so that the excision can be complete and with the best cosmetic result. In this report we discuss localization methods, from the simplest to the most complicated ones. The commonest method has the advantage of employing no special instruments, and it is very simple, safe and fast. It requires a skilled hand and a little training. Instrumental methods are then discussed, from the simple dedicated compressor to the stereotactic techniques and, finally, the role of ultrasonography both in preoperative localization and in cytologic biopsy. The importance of mammographic examination of the surgical specimen is also stressed.