A 59-year-old man presented with a chief complaint of epigastric pain. He was admitted to our hospital with high fever and severe inflammatory signs (CT) scan revealed inflammatory changes in the gastrosplenic ligament and multiple low-density areas containing air in the spleen and intrahepatic portal vein ; however, abdominal examination did not reveal any remarkable findings. There were no findings suggesting intestinal ischemic change. On the second hospital day, disseminated intravascular coagulation occurred. After conservative therapy, his condition improved temporarily, but high fever developed again. Computed tomography CT scan showed a splenic abscess, and emergency splenectomy was therefore performed. Intraoperative findings suggested that the splenic abscess had developed from colonic disease, and partial colectomy of the splenic flexure was therefore performed. The pathological findings revealed that the splenic abscess had developed from colon penetration associated with colon cancer. Owing to the postoperative failure of sutures, colostomy was performed. The postoperative course was uneventful, and chemotherapy was started. Eleven months have passed without relapse. Splenic abscess caused by colon penetration associated with colon cancer is a rare condition, which can suddenly deteriorate and result in serious complications. To the best of our knowledge, there have been only 9 reports similar to those of the present case.