The Authors show their preliminary experience with the sentinel lymph node biopsy (SLNB) in clinical early invasive breast cancer (T1N0). During a period of 15 months, forty-two patients were submitted to SLNB upon Tc99-colloid albumin injection and SLN identification by lymphoscintigraphy. The middle number of lymph nodes found in the SLNB was 1 (1-3), whereas the middle number of lymph nodes identified in level I/II ALND specimens was 15. The SLN was identified with success in all cases (100%). The axilla was positive for metastasis in 4/42 cases. The SLN was positive in all four cases in which nodal metastasis was identified. The negative predictive value of SLN was 100%. The SLN was the only site of metastasis in 3/4 cases. The SLN pathological status accurately reflected the lymphatic basin status, but further investigation is needed to define the optimal timing of colloid injection and method of examination of the SLN.