After some preliminary remarks upon pathophysiologic and anatomo-surgical aspects, the main complications of axillary lymph-nodal dissection for breast cancer treatment are reported. The role of surgical technique is particularly underlined and also the importance of proper management of wound and surgical drainage post-operatively are pointed out. Author describes, finally, the necessity of an adequate knowledge of lymphatic drainage not only of mammary region, but also of surrounding area, in order to prevent lesions to lymphatic pathways, particularly to those draining upper arm at the same site of breast cancer.