Reoperations for breast cancer predispose to a higher risk of postoperative wound infections than primary procedures. We accomplished a retrospective chart review of 320 women who underwent multiple breast cancer procedures between 10/97 and 8/02. The mean number of procedures was 2.4 (range, 2-5). The overall incidence of wound infection was 6.1 per cent. Wound infections developed, on average, 12 days after surgery (range, 2-30). There was a statistically significant difference in the incidence of wound infection comparing the initial procedure versus the subsequent operation (1.6% vs. 9.4%, P < 0.001). This was also seen with reoperation after an operative biopsy compared to operation after a core biopsy (11.1% vs. 9.7%, P < 0.01). The incidence was increased to 22.0 per cent when the initial operation involved lymph node dissection (sentinel lymph node biopsy or complete axillary lymph node dissection). Wire localization did not increase the incidence of postoperative wound infections, and prophylactic antibiotics were associated with a decreased incidence of wound infection in the reoperative setting. The incidence of wound infection is increased with reoperation after operative biopsy compared to operation after core biopsy and is further increased when the initial biopsy involved lymph node dissection.