Prior breast augmentation in patients desiring post-mastectomy reconstruction provides a unique opportunity for capsular preservation and immediate, single-step implant reconstruction. We report a case series of a single-surgeon experience with immediate implant reconstruction after skin-sparing mastectomy in patients with prior subpectoral augmentation. Final implant volumes, complications, and outcomes were examined. Twenty patients (15 bilateral, total 35 breasts) were included. Eighteen (90%) patients were treated for cancer. Mean augmentation-to-reconstruction interval was 9 years (range, 3-19 years). Mean patient age was 45.1 years (range, 37-64 years). Eight patients (40%) received postoperative chemotherapy and two (10%) radiation. Mean mastectomy weight was 321 g. Mean weight of the implants removed was 346 g. Mean volume of new implants was 487 mL. All patients underwent capsulotomy (100% superior, 85% medial, 30% inferior, 5% lateral). Mean operative time was less than 1 hour for bilateral reconstruction. With average follow-up of 25.6 months, 2 patients were re-operated on for asymmetry (implant malposition, synmastia). Thirty-day complications included 1 implant loss due to infection, 1 drain placement with implant salvage, 1 hematoma requiring evacuation, and 1 cellulitis treated with antibiotics. There were no late complications and no capsular contractures. None have required further oncologic surgery. No cancer recurrences have been detected. In patients who desire prosthetic reconstruction similar to their original submuscular augmentation, capsule preservation and implant replacement with a larger prosthetic inserted within the old capsule is safe, fast, and aesthetically pleasing without compromising oncologic principles.