Treatment of a locoregional recurrence of breast cancer after mastectomy remains a clinically challenging problem. Often these patients have undergone prior radiotherapy and chemotherapy. Therapeutic options usually include resection or additional radiation; however, the long-term control rates are often suboptimal with these approaches. Data from several randomized trials suggest that the addition of hyperthermia to radiation can increase the response rate for such local recurrences. Therefore, in settings where the available therapies are unlikely to yield local control (e.g., local/regional recurrence after prior radiation), a reasonable option to consider is radiation with hyperthermia as a radiation sensitizer. This article reviews the rationale and supporting literature for this recommendation.