Abstract: As more women put off pregnancy until their 30s and beyond, the possibility of pregnancy-associated breast cancer (PABC) will rise. Treatment options for patients with PABC need to consider possible harm to the fetus. The goal of this study is to review our institution’s experience with sentinel lymph node (SLN) biopsies in patients with PABC. A prospectively accrued breast Institutional Review Board (IRB) approved data base was searched under separate IRB approval for cases of SLN biopsy in patients with PABC. Ten patients were identified between 1994 and 2006 out of 5,563 patients. A chart review was performed on all 10 patients. Ten patients with PABC and an average gestation age of 15.8 weeks underwent SLN biopsy. All patients successfully mapped. Positive SLN were identified in 5/10 patients (50%) while there was no evidence of metastases in 5/10 patients (50%). 9/10 (90%) of patients went on to deliver healthy children without any reported problems. One patient (10%) decided to terminate her pregnancy in the first trimester following surgery prior to the start of chemotherapy. SLN biopsy can safely be performed in patients with PABC with minimal risk to the fetus. By performing a SLN biopsy, a large proportion of patients with PABC may be spared the risk of a complete axillary lymph node dissection.