The ability to more definitively plan breast reconstruction after obtaining final histologic analysis of the sentinel lymph node biopsy (SLNB) has led several groups to advocate a staged approach to SLNB and mastectomy. Certain disadvantages are inherent in that approach, including increased patient morbidity, financial expense, and inconvenience. A retrospective review was conducted 195 procedures in which mastectomy and SLNB were performed in a single stage with immediate breast reconstruction (IBR) over a 10-year period. Long-term outcomes were analyzed within the context of patient characteristics and SLNB results. Intraoperative SLNB analysis was found to be a reliable method for planning IBR, as there were no patients noted to have untoward sequelae as a result of a false-negative SLNB, and the probability of postmastectomy radiation therapy was predictable based on the intraoperative SLNB results. We advocate that SLNB be performed in a single stage with mastectomy and IBR.