Ductal carcinoma in situ (DCIS) is a heterogeneous and complex disorder that has changed greatly as an entity over the past few decades. Despite an overall favorable prognosis and evidence-based recommendations from randomized trials, the clinical management of DCIS varies considerably among surgeons. While the goal is to achieve maximal local control with minimal morbidity, surgeons at times both over- and undertreat these patients. Currently, the rates of mastectomy and contralateral prophylactic mastectomy have been dramatically rising without clear evidence of better control. Radiotherapy is omitted in about one- half of patients undergoing lumpectomy. Tools to help stratify patients at highest risk for DCIS or invasive recurrence may assist in determining appropriate therapy. This article reviews some of the areas of controversy in the surgical approach to DCIS, including breast conservation versus mastectomy, the use of radiotherapy, the appropriate extent of margins, and the criteria for including sentinel nodal biopsy. © 2010 Wiley Periodicals, Inc.