To evaluate the performance and feasibility of sentinel lymph node biopsy in early breast cancer patients using patent blue dye. From March 2004, we are consecutively enrolling breast cancer patients with tumor size less than 5 cm with no clinically palpable axillary lymph nodes in this feasibility study. So far, 21 patients underwent sentinel lymph node biopsy using 1.0% patent blue dye injection around the tumor followed by axillary dissection. Sentinel lymph node biopsy was compared with axillary dissection for its ability to accurately reflect the final pathological status of the axillary nodes. Age of patients ranged form 32-67 years old with mean age of 46.72 years. Fifty seven percent of patients were postmenopausal. Patients with T1 lesions were 8 and T2 were 13. The sentinel lymph node/s were successfully identified in 20 out of 21 patients (95.0%). The number of sentinel lymph nodes ranged from 1 to 5 (average 2.0) and non-sentinel nodes ranged from 5-22 (average 12.0). Infiltrating ductal carcinoma was diagnosed in 15 patients, DCIS with early invasion in 4 patients, invasive lobular carcinoma in 1 and medullary carcinoma in 1 patient. Of the 20 patients in whom sentinel lymph nodes were successfully identified, nodes were positive in 35.0% (7/20) of patients. All the positive nodes were detected in group with T2 lesions. SLNs were the only positive nodes in 2 patients. There were no false negative patients, yielding an accuracy of 100.0%. Lymphatic mapping using patent blue dye alone is technically feasible for patients with small (T1 or T2) palpable breast tumors. The sentinel node can be reliably identified in the majority of these patients, and its histology reflects that of the axilla with a high degree of accuracy. This method is very useful in economically backward countries as it involves less expensive material.