Halsted's principle of radical mastectomy influenced cancer treatment for decades. Randomized controlled trials resulted in a paradigm shift to less radical surgery and the use of adjuvant therapies. Oncologic reconstruction performed by plastic surgeons has evolved, ranging from skin grafts and local flaps for smaller defects to pedicled flaps and free flaps for larger and more complex defects. Immediate reconstruction facilitates resection is oncologically safe and contributes to meaningful improvements in quality of life. J. Surg. Oncol. 2016;113:852–864. © 2016 Wiley Periodicals, Inc.