The surgical techniques and clinical results of quadrantectomy as a form of breast-conserving surgery are described. A quadrantectomy is a breast-conserving technique including wide resection and tumorectomy. A quadrantectomy is designed to remove an anatomic segment of breast tissue (duct-lobular system). It has the advantage of greater surgical curability than other conserving techniques in cases with ductal spread, because breast cancer arising in the terminal duct often spreads in the duct-lobular system. However, quadrantectomy poses some cosmetic problems due to the large volume of breast tissue excised. Additionally, quadrantectomy has failed to show better results in local recurrence rates compared with wide resection. Therefore quadrantectomy should be limited to breast cancer with segmental and wide ductal spread. It is important to determine the surgical technique that compromises between local curability and cosmetic results for each patient with breast cancer.