- The most important prognostic factor after breast conservation surgery is surgical margin involvement. In cases where surgical margins are involved, the patient must return to the OR for a second operation. Therefore, there is a need for an intra-operative tool to assess the surgical margins. The Margin Probe technique was developed for this need. In this article we present our experience at the "Barzilai" Medical Center using the Margin Probe during breast conservation surgery. The Margin Probe technique is added to routine standard of care at "Barzilai" Medical Center. The device sends radiofrequency signals to the resected tissue and spectroscopy analysis provides data to the surgeon about the involvement of the surgical margins. In cases where the device signals for positive margins, the surgeon expands the resection, in order to avoid a second surgery in the future. From sixty four patients who underwent breast conservative surgery, twenty four (37.5%) underwent intraoperative additional re-excision due to positive margin signals from the Margin Probe device. From those patients, nine patients (37.5%) indeed had surgical margins involvement in the pathology analysis. From all patients, four (6.25%) underwent a second surgery, while only one patient had a false negative measurement from the device. According to our experience, using the Margin Probe technique is feasible, safe and reduces the rate of repeated operation.