We report the case of an 80-year-old man given a diagnosis of pancreatic intraductal papillary-mucinous carcinoma (IPMC) and early gastric cancer. He refused surgery, therefore endoscopic mucosal resection (EMR) for gastric cancer and careful observation were performed. Penetration of the IPMC to the stomach was observed 3 months later. Ten months after the initial diagnosis, he was found to have a splenic abscess and was subsequently treated by antibiotics and percutaneous drainage, and a fistula between the IPMC and the splenic abscess was observed. We suppose IPMC penetration to the spleen and bacterial transmission from the stomach through the fistula caused the splenic abscess. While IPMC is recognized as a low-grade malignancy, some cases of invasive carcinoma with fistulation to adjacent organs have been reported. To the best of our knowledge, this is the first case of IPMC associated with splenic abscess due to pancreatosplenic fistula.