Background: Electrocautery is commonly used for various surgical procedures such as mastectomy is used to stop bleeding and perform dissection. It has been suggested that thermal spread can cause flap necrosis, wound infection, prolonged drainage, and damage to the surrounding tissues. Several studies have reported that the LigaSure Small Jaw device can reduce the incidence of seroma. The present study aimed to evlaute the effectiveness of monopolar electrocautery compare to LigaSure™ Small Jaw in reducing the postoperative seroma in patients with breast cancer who undergoing radical mastectomy. Patients and methods: this study included 40 females with breast cancer who attending for modified radical mastectomy. The patients were divided equally into the monopolar electrocautery group and the LigaSure™ Small Jaw group. Results: There was statistically significant difference between groups as regard duration surgery. Also, amount of blood loss was statistically larger among Electrocautery group than LigaSure™ Small Jaw group.As regard Post-operative complications ,seroma was the commonest complication followed by flap necrosis and wound sepsis respectively, with no difference between both groups. There was statistically significant difference between different VAS readings at different timings between studied 2 groups. Conclusion: LigaSure™ Small Jaw was more effective than Electrocautery in reducing the intraoperative and postoperative complication in breast cancer patients undergoing modified radical mastectomy.