The increasing incidence of non-palpable breast cancers, partly driven by the adoption of screening, presents a challenge with a higher risk of involved margins. To prevent margin involvement, a comprehensive preoperative assessment is essential, as factors such as Invasive Lobular Carcinoma (ILC), ductal carcinoma in situ (DCIS), aggressive tumour biology (e.g. triple-negative disease), dense breasts, and prior neoadjuvant therapy increase the risk of margin positivity. Prevention strategies emphasize rigorous preoperative planning utilizing multimodal imaging and modern localization techniques. Intraoperative interventions such as cavity shaving and oncoplastic surgery may help decrease such risk. Advanced intraoperative margin assessment technologies showed strong potential to improve margin clearance. With positive margins, the management requires a multidisciplinary team approach, prioritizing re-excision to secure local control. Re-excision is generally the first treatment of choice and should not compromise the patient’s oncological outcome, even if multiple re-excisions are required. The role of frozen section is uncertain and should only be considered on a case-by-case basis. The oncoplastic technique and locoregional flap may be beneficial if a significant defect occurs, while breast conservation remains the preferred approach. Conversion to mastectomy is reserved for extensive disease or unfavourable breast-to-tumour ratios. In selected older or comorbid patients, a targeted radiotherapy boost may be considered an acceptable alternative to reoperation. In summary, despite technical advances, the involved margin after breast-conserving surgery (BCS) persists, especially in non-palpable tumours. Multidisciplinary team (MDT) is essential, and treatment choices should be thoroughly discussed with the patient to achieve the best outcome.