Background And Objective: The aim of this study was to evaluate the safety of same-day mastectomy, with or without a sentinel node biopsy (SNB) and/or axillary lymph node dissection (ALND).Methods: In this retrospective study, we reviewed 913 consecutive women who underwent a simple mastectomy for breast cancer between the years 2014 and 2019 and were treated either with same-day surgery (SDS) or an overnight stay (OS) regime. We reviewed all surgical complications, any unplanned return to care (RTC) and the rehospitalization rate for 30 postoperative days.