Background: In addition to conventional breast-conserving surgery (BCS), oncoplastic breast surgery (OBS) is an operation technique that strives simultaneously to increase oncological safety and patient's satisfaction. It is the combination of the best-proven techniques in plastic surgery with surgery for breast cancer. In a growing number of indications, OBS overcomes the limit of conventional BCS by allowing larger resection volumes while avoiding deformities. The aim of our retrospective study (2012-2014) was to compare oncological outcomes of OBS versus BCS., Methods: We compared two groups of patients with primary non-metastatic breast tumours: group A (n = 291), where BCS was performed, versus group B (n = 52), where OBS was performed. Surgical interventions were performed in German and Swiss teaching hospital settings. The surgeon for group B had subspecialist training in OBS. We assessed outcome in term of re-excision rates, resection margin and complications., Results: Groups were homogenous (no significant differences in terms of age, tumour size, tumour type or grade). The resection margin was larger in group B (7 mm) than in group A (3 mm). Re-excision rate of group B (8%) was significantly lower than in group A (31%). Complication rates were comparably low in groups A and B., Conclusion: Despite the limits of retrospective design, our study confirms that OBS is safe and reduces the re-excision rates and the need for further surgery. OBS has the potential to improve oncological care and should be more widely adopted., (© 2019 The Authors. ANZ Journal of Surgery published by John Wiley & Sons Australia, Ltd on behalf of Royal Australasian College of Surgeons.)