The prognosis for patients with carcinoma of the body and tail of the pancreas is extremely poor. We analyzed the effectiveness of intraoperative radiotherapy (IOR) from the viewpoint of the cumulative survival rate and pain relief. The prognosis of patients who underwent IOR with/without resection was significantly longer than for patients without IOR (p < 0.0001). Better pain relief was obtained by IOR. Although a randomized prospective study is required, resection and IOR will be the central treatment modalities for carcinoma of the body and tail of the pancreas.