Background: Nipple-sparing mastectomy (NSM) is emerging as the standard of care for treatment of breast cancer because of its oncologic safety and superior aesthetic outcomes. However, ischemia or necrosis of the skin flap and/or nipple-areola complex remain frequent complications. Hyperbaric oxygen therapy (HBOT) has emerged as a potential adjunct for flap salvage, although it is not currently a widely accepted practice. Here we review our institution's experience using a protocol of HBOT in patients with signs of flap ischemia or necrosis after NSM. Methods: Retrospective review identified all patients treated with HBOT at our institution's hyperbaric and wound care center because of signs of ischemia after NSM. Treatment parameters consisted of 90-minute dives at 2.0 atmosphere once or twice daily. Patients unable to tolerate dives were considered a treatment failure, whereas those lost to follow-up were excluded from analysis. Patient demographics, surgical characteristics, and treatment indications were recorded. Primary outcomes assessed were flap salvage (no operative revision), need for revision procedures, and treatment complications. Results: A total of 17 patients and 25 breasts met the inclusion criteria. The mean ± SD time to initiation of HBOT was 9.47 ± 12.7 days. The mean ± SD age was 46.7 ± 10.4 years, and mean ± SD follow-up time was 36.5 ± 25.6 days. Indications for NSM included invasive cancer (41.2%), carcinoma in situ (29.4%), and breast cancer prophylaxis (29.4%). Initial reconstruction included tissue-expander placement (47.1%), autologous reconstruction with deep inferior epigastric flaps (29.4%), and direct-to-implant reconstruction (23.5%). Hyperbaric oxygen therapy indications included ischemia or venous congestion for 15 breasts (60.0%) and partial thickness necrosis for 10 breasts (40.0%). Flap salvage was achieved in 22 of 25 breasts (88.0%). Reoperation was required for 3 breasts (12.0%). Hyperbaric oxygen therapy-related complications were observed in 4 patients (23.5%), which included 3 patients with mild ear pain and 1 patient with severe sinus pressure leading to treatment abortion. Conclusions: Nipple-sparing mastectomy is an invaluable tool for breast and plastic surgeons to achieve oncologic and cosmetic goals. However, ischemia or necrosis of the nipple-areola complex or mastectomy skin flap remains frequent complications. Hyperbaric oxygen therapy has emerged as a possible intervention for threatened flaps. Our results demonstrate the utility of HBOT in this population to achieve excellent NSM flap salvage rates.