Background: Breast cancer is the most frequent neoplasm in women. Axillary lymph nodes dissection represents the treatment of choice in locally advanced breast cancer for prognostic and curative purposes. Seroma formation, an abnormal collection of fluid in the dead space of the axilla, is described in Literature with a wide range of incidence (3-85%). It is a source of significant morbidity and discomfort. The aim of the study is to compare the different haemostasis devices used in breast surgery, investigating the eventual superiority of an instrument among the others in terms of intraoperative and postoperative outcome, especially of seroma formation. Methods: Clinical cases of female patients undergone axillary lymph nodes dissection for local advanced breast cancer between January 2013 and July 2017 at the Surgery Unit of University of Campania "Luigi Vanvitelli" were retrospectively reviewed. Patients were divided into four groups, according to device utilized during surgery: Electrocautery, Harmonic Scalpel, LigaSure and Thunderbeat. All patients underwent II level axillary lymph nodes dissection associated to radical mastectomy or quadrantectomy. Results: One hundred consecutives patients were enrolled in the study. Intra-operative blood loss resulted statistically significant different (P < 0,01) between the Electrocautery group (94,7 ml) and the Thunderbeat group (57,2 ml), while the Harmonic Scalpel group and the Ligasure group, despite presented a lower amount of blood loss, did not differ significantly. Drainage volume resulted significantly lower (P = 0,002) in the comparison between the Electrocautery group and the Thunderbeat group; the Ligasure group and Harmonic Scapel group showed no difference between them and Electrocautery group. About the seroma formation, the Electrocautery group resulted affected by the highest seroma formation rate (64%). Seroma incidence in Harmonic Scalpel group was 24%, in Ligasure group was 44%, while Thunderbeat group showed the lowest presentation of seroma with 16%. Conclusions: In patients affected by breast cancer requiring axillary lymphnodes dissection, the use of advanced hemostasis devices is highly desirable. Among the non-traditional tools, Thunderbeat resulted to be superior in terms of reduction of intra-operative blood loss and post-operative drainage output, moreover associated to a substantial reduction of postoperative seroma incidence.