Postoperative seroma is still the main complication after a latissimus dorsi (LD) flap procedure. The etiology of seroma is currently thought to comprise tissue fluids resulting from inflammatory reactions in affected tissue caused by the use of monopolar electrocautery (EC). It is possible that seroma formation can be reduced by using alternative devices such as the PEAK PlasmaBlade (PPB), which provides atraumatic scalpel-like cutting precision while the blade temperature remains close to body temperature. The subjects were 44 patients who underwent breast reconstruction with LD flaps from August 2015 to April 2017. They were retrospectively split into groups treated with a PPB (n = 21) and with conventional EC (n = 23). Outcomes such as rate of seroma formation, total drain discharge volume, indwelling period of drainage at the donor site, length of hospital stay, and operation time were compared between the 2 groups. The incidence of seroma was significantly lower in the PPB group (19.0%) than in the EC group (47.8%). The total drain discharge volume was significantly lower and the indwelling period of drainage and length of hospital stay were significantly shorter in the PPB group. In summary, use of PPB in an LD flap procedure can reduce seroma formation and the lengths of the drainage period and the hospital stay.