Lower axillary lymph node dissection (lower parts of both the level I and II elements below the second intracostobrachial nerve) and level I and II lymph node dissection were performed on breast cancer patients (n = 54), and the results with the two methods were compared in terms of the status of detected lymph node metastases. For Stage I, N0 cases, the results for pathological classification lymph node metastases (pN) were in agreement between the two dissection methods. And, the occurrence of operated arm swelling wasn't recognized when a side effect was examined with the case (n = 28) that only lower axillary dissection was carried out in case of an operation for breast cancer. Accordingly, it was surmised that lower axillary dissection provides accurate pN information for Stage I, N0 cases. These results indicate that lower axillary dissection has the potential to become an effective, standard surgical procedure for breast cancer patients whose preoperative disease stage is Stage I.