Background: Problems in patients who could not get adequate surgical margins (SM) and good cosmetic results with breast-conserving surgery (BCS) have been overcome with the introduction of oncoplastic surgery (OPS) methods. The purpose of this study was the documentation of level II techniques and the presentation of long-term survival results. Methods: The data on patients who had been prospectively registered in the database between 2007 and 2017 and who had been treated with level II OPS due to invasive breast cancer were examined. Results: A total of 1,074 patients were included in the study. The most commonly applied level II oncoplastic techniques were performed in the upper outer quadrantectomy with racquet incision in 334 (31%) patients, inferior pedicle flaps in 294 (27.3%), and vertical mammoplasty in 140 (13%). Reexcision was performed in 96 patients (8.9%). Total breast conservation rate was 96%. Five-year disease-free survival (DFS) was 88%, local recurrence-free survival (LRFS) 93.6%, and overall survival (OS) 96%. Ten-year DFS was 72%, LRFS 85.4%, and OS 90.2%. Conclusion: Level II OPS techniques have low reoperation and complication rates and a high rate of breast protection. The success of these techniques has been demonstrated in terms of long-term local control. Awareness of the fact that many patients who undergo OPS will not lose their breasts should be created, and regular training programs for OPS techniques should be conducted especially in developing countries. By revealing these results, it is hoped that the OPS and breast conservation rates will increase.