Two recent trials have demonstrated superior locoregional control, disease-free survival, and overall survival in node-positive breast cancer patients with the addition of postmastectomy radiation therapy to mastectomy and chemotherapy. Based on these results, there has been an increased use of postmastectomy in patients with early-stage breast cancer. The inability to determine which patients will require postmastectomy radiation therapy has increased the complexity of planning for immediate breast reconstruction. There are two potential problems with performing an immediate breast reconstruction in a patient who will require postmastectomy radiation therapy. One problem is that postmastectomy radiation therapy can adversely affect the aesthetic outcome of an immediate breast reconstruction. Several studies have evaluated the outcomes of breast reconstructions that were performed before radiation therapy and have revealed a high incidence of complications and poor aesthetic outcomes. Furthermore, these studies have found that often an additional flap is required to restore breast shape and symmetry. The other potential problem is that an immediate breast reconstruction can interfere with the delivery of postmastectomy radiation therapy. During planning for immediate breast reconstruction, it is imperative to carefully review the stage of disease and the likelihood the patient will require postmastectomy radiation therapy. Unfortunately, the ability to detect and predict the presence or extent of axillary lymph node involvement is limited, and the need for postmastectomy radiation therapy is usually not known until after mastectomy. In all cases of decision making regarding possible postoperative radiation therapy and whether or not to perform immediate breast reconstruction, the situation should be discussed at a multidisciplinary conference or addressed among the various medical, surgical, and radiation teams, with active participation by the patient. Immediate breast reconstruction probably should be avoided in patients known to require postmastectomy radiation therapy and delayed until it is certain the therapy will be needed in patients who may require the therapy.