Use of internal mammary vessels during breast reconstruction provides information on part of the internal mammary chain lymph nodes (LNs). It was evaluated whether our current practice of screening should be changed to identify those delayed breast reconstruction patients with tumor-positive internal mammary nodes (IMNs) and whether breast reconstruction should be continued, in case suspicious IMNs were found intraoperatively. From February 2002 to December 2004, 81 patients had received 98 deep inferior epigastric perforator flaps for delayed breast reconstruction. Prospectively collected data for suspicious internal mammary LNs were evaluated. In 13 patients (16%) who had received a delayed breast reconstruction, macroscopically suspicious LNs were detected in the course of the internal mammary chain. Three patients (4%) had a pathologic diagnosis of malignancy, which was found to match their primary tumor. No relationship between positive internal mammary chain LNs and location of the primary tumor, TNM-stage, or previously administered adjuvant therapy was found. Suspicious internal mammary chain LNs found during recipient vessel dissection for breast reconstruction can have important consequences for treatment of malignant disease in individual patients. Presented data do not support changing the current perioperative approach of delayed breast reconstruction.