Background: Tumescence is the injection of local anesthetic and crystalloid into the subcutaneous tissue to establish a bloodless plane for surgical dissection. The aim of our study was to evaluate outcomes after mastectomy with tumescent technique compared to electrocautery dissection. Methods: We conducted a single-institution retrospective evaluation of patients who underwent mastectomy between 2007 and 2011. The tumescent technique was performed by injecting 1% lidocaine with epinephrine mixed in a 10% ratio with lactated Ringer solution into the mastectomy flaps followed by sharp dissection. Significance testing was done to evaluate for outcome differences between the two surgical groups. Results: Among the 134 patients, 64 underwent electrocautery and 70 underwent tumescent-assisted dissection. The overall complication rate was 21.6% (tumescent, 20.0%; electrocautery, 23.4%, P = 0.63). Flap necrosis requiring operative debridement was the most common complication in the tumescent group (n = 6). On multivariate analysis, tumescent technique was not associated with an increased complication rate. Immediate reconstruction was the only factor that increased the risk of complication (odds ratio 12.95, P < 0.001). Conclusions: The tumescence surgery technique should be utilized with caution in patients undergoing immediate reconstruction, as a trend for higher complication rates was observed in these cases, and flap viability is particularly important in this setting. Future prospective studies are needed to further evaluate blood loss, operative time, postoperative pain, and duration of drainage catheters after tumescent mastectomy technique.