Although radiation and surgery have been combined for the treatment of cancer in humans and animals since the 1920s, little has been written about the methods of combining radiation and surgery and the efficacy of this combination for the treatment of animal tumors. This article reviews the rationale for combining radiation and surgery for the treatment of cancer and the ways in which these two modalities can be combined with emphasis placed on the advantages and disadvantages of preoperative and postoperative radiotherapy. The role of preoperative and postoperative irradiation for the treatment of various animal tumors is discussed. Directions for future clinical trials are pointed out. Finally, the importance of surgeons and radiation oncologists communicating with each other and participating in cooperative treatment methods is stressed.