Purpose: Sentinel lymph node mapping is now an established method of accurately staging the axilla in patients with breast cancer. However, the augmented breast may pose an interesting challenge to this procedure. Does augmentation mammoplasty alter breast architecture enough to change patterns of lymphatic drainage? The purpose of our study is to determine the reliability of sentinel lymph node mapping in patients with augmented breasts who subsequently develop breast cancer. Methods: A retrospective review (1995-2001) identified patients with augmented breasts with invasive breast cancer who underwent breast conservation therapy with sentinel lymph node mapping. Lymphazurin dye was injected into the parenchyma surrounding the tumor. The sentinel node was identified through an axillary incision as the first blue lymph node. Nuclear lymphoscintigraphy was not used. A standard axillary node dissection (ALND) was performed if the sentinel lymph node was positive for metastasis. Results: Seven patients,between ages 33-62(mean age 50),had Stage I or Stage II disease. All tumors were infiltrating ductal carcinoma ranging in size 0.5-1.8cm (T1). Five patients had tumors located in the upper outer quadrant of the breast, one was located immediately superior to the nipple, the other was inferior to the nipple. All breast implants were pre-pectoral in location placed through an infra-areolar incision. Sentinel lymph nodes were identified in all patients (100%). Three patients (43%) had positive sentinel nodes, two proceeded with axillary node dissections while one patient declined. One patient with a negative sentinel node underwent ALND with all nodes negative for metastasis. Three patients (43%) with negative sentinel nodes were followed clinically. To date, there have been no local or regional recurrence with a median follow-up time of 2.5 years. Conclusions: Sentinel lymph node mapping is the preferred method of axillary node staging in patients who have undergone augmentation mammoplasty, with the exception of implants placed in a trans-axillary fashion.