Axillary node dissection for breast cancer is important for staging and prognosis. "Sentinel nodes" are the first nodes into which primary cancer drains. Identification, removal and pathological examination of those nodes indicates whether completion of axillary lymphadenectomy is required. The sentinel nodes are identified using a vital dye injected at the primary tumor site. With this technique we were able to identify sentinel nodes in 46 of 48 (95%) women examined. An average of 2.7 +/- 1.2 nodes were identified as sentinel nodes. In 81% of cases there was a correlation between involvement of sentinel nodes and of other axillary nodes as well. In 10% of patients sentinel nodes were involved with tumor while other axillary nodes were negative. The major problem in routine application of this is relationship in surgical decisions is reliable real time pathological identification of lymph node involvement by tumor.