Purpose: To evaluate the accuracy and feasibility of sentinel lymph node biopsyly by using radiopharmaceuticals for sentinel lymph node mapping. Methods: From April 1999 to October 2001, lymphatic mapping by using radiopharmaceuticals( either99mTc-antimony sulfide or 99mTc-sulfur colloid ) injection into subdermal directly overlying the tumor was performed on 79 patients with early breast cancer followed by SLND, then all patients received breast opreations including standard axillary lymph nodes dissection ( ALND). To analyze the results of SLND performed by radiopharmaceuticals. Results: The sentinel nodes were successfully identified by lymphoscintigraphy in 67 of 75 cases (89. 33%). Of the 68 patients in this study whose sentinel nodes were identified both by lymphoscintigraphy and handhold ?-probe ,65 patients' SLNs could predict the axillary status accurately(95. 59%) . The false negative rate is 8. 33%(3 of 36). We failed to identify SLN in 9 cases and found 3 cases SLNs to be false negative in the first 28 cases while there were only 2 cases whose SLN could not be identified and no false negative in the other 51 cases. The differences between the two groups were statistically significant(P