Introduction: (Pre)malignant lesion in the breast requiring mastectomy conventionally may be treated with breast conservation by using oncoplastic breast surgical techniques, which is called therapeutic mammaplasty. However, no reliable data has been published so far as regards the oncological safety of this method. Aim: The aim of the authors was to analyse the oncological safety of therapeutic mammaplasty in a series of patients. Method: 99 patients were treated with therapeutic mammaplasty and data were collected in a breast surgical database prospectively. Results were analysed with respect to intraoperative, postoperative and long-term oncological safety. Results: Incomplete resection rate was 14.1%, which correlated with tumour size (p = 0.023), and multifocality (p = 0.012). Time between surgery (therapeutic mammaplasty) and chemotherapy was similar to time between conventional breast surgeries (wide excision, mastectomy, mastectomy with immediate reconstruction) and chemotherapy (mean 29–31 days; p<0.05). Overall recurrence rate was 6.1%, locoregional recurrence rate was 2% during 27 month (1–88) mean follow-up. Conclusions: Since literature data are based on relatively short follow-up and low patient number, it is highly important that all data on therapeutic mammaplasty is collected in a prospectively maintained breast surgical database in order to determine true recurrence after long-follow-up. Orv. Hetil., 2013, 154, 1291–1296.