Breast cancer is one of the leading killers among women the world over. Widespread mammographic screening programs have led to almost 20% of breast cancers being detected when they are radiologically visible but clinically impalpable. For the localization of these cancers before surgical excision, the Kopan hook wire is the standard technique, but the extent of margins excised still needs to be ... [Show full abstract] determined. In this study, we have evaluated the accuracy of specimen mammogram (SM) with digital breast tomosynthesis (DBT) for margin assessment by comparing it to the excised margins as measured in final histopathology. This is a prospective observational study of patients with radiologically suspicious impalpable breast lesions. The patients underwent ultrasound-guided hook wire placement followed by excision of the lesion, subjected to digital tomosynthesis mammogram, and margins were revised on table when indicated. These findings were correlated with final histopathological margin. Our study included 30 patients and out of the 6 lesions, which showed positive margins on specimen mammography, 4 were histologically confirmed to have tumour at the surgical margin and 2 were confirmed to be tumour free. All DBT-positive margins were re-excised at the time of primary surgery. Individual comparison of the margins revealed a good agreement and high level of correlation between DBT and histopathology margins. None of the cases required a second surgery for margin revision. It can be concluded that specimen mammogram with DBT can be used as a reliable tool for intraoperative surgical margin assessment in non-palpable breast lesions to reduce rate of margin revision as well as reduce the volume of breast excised without compromising the oncological safety of the procedure.