As breast cancer therapies and associated oncologic outcomes continue to improve, greater attention has been placed on quality-of-life issues after breast cancer and breast cancer risk-reducing treatments. The loss of sensation that typically occurs after mastectomy can have significant negative psychological, sexual, and functional impact on patients after surgery. Further, injury of nerves not only leads to numbness, but can also cause chronic neuropathic pain, which can be very debilitating to affected patients. In order to minimize these impacts, there is expanding uptake of surgical approaches that preserve nerves at the time of mastectomy and reconstruct injured nerves either during mastectomy or during delayed reconstruction. These advances have been facilitated by anatomic studies investigating different variants of intercostal anatomy and better understanding the course of the nerves innervating the mastectomy skin and nipple-areolar complex (NAC). With improved knowledge of the intercostal nerve anatomy, surgeons are able to carefully preserve nerves at the time of mastectomy, thus improving sensory outcomes. Additionally, nerve reconstruction techniques have advanced, particularly with newer nerve allograft technologies, which allows for nerve reconstruction to be done both at the time of mastectomy, as well as in a delayed fashion. The focus of this article is to describe the current state of sensory preservation and immediate reinnervation at the time of mastectomy and the advances that have allowed for these new approaches.