Donor-site seroma persisting for > 3 weeks is the most common complication of latissimus dorsi (LD) flaps for breast reconstruction after mastectomy. Conservative treatment is insufficient for refractory seroma resolution. We report the results of surgical intervention for refractory donor-site seroma. Between January 2012 and April 2018, 319 patients undergoing breast reconstruction using an LD flap at our hospital were treated with conservative therapy if seroma was found. Refractory seroma of > 3 months' duration was observed in five patients (1.6%). Before surgery, the precise location and extent of the capsule were determined using chest computed tomography, and surgical intervention was planned. An en bloc capsulectomy was performed after confirming the internal capsule. Simultaneously, a quilting suture, bolster suture, and fibrin sealant were applied to prevent recurrence. The mean age of the patients with refractory seroma was 45.4 ( ± 7.3) years, and their mean body mass index was 31.0 ( ± 6.2) kg/m2. All patients underwent breast reconstruction with an extended LD flap or extended LD flap with a silicone implant after total mastectomy. During the follow-up period of ≥ 10.4 months, a mean of 34.4 ( ± 10.4) needle aspiration procedures were performed, and a mean of 12.8 ( ± 2.2) cc of seroma fluid was removed each time. Intraoperatively, the formation of a capsule with a well-defined border was confirmed; all patients showed complete resolution of donor-site seroma within 4 weeks after surgical intervention. Refractory donor-site seroma occurrence was rare in the cases assessed. Surgical intervention was successful in cases of refractory donor-site seroma unsuccessfully treated with conservative therapy and is thus one of the most effective methods for complete resolution of refractory seroma.Level of Evidence IV This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.