A 75-year-old woman with abdominal pain and vomiting was admitted to our hospital. Colonoscopy showed an advanced colon cancer that encompassed the entire circumference of the descending colon's lumen. The patient was diagnosed with occlusive ileus associated with the colon cancer. She had been watched for liver cirrhosis due to the hepatitis C virus and received radiofrequency ablation therapy for hepatocellular carcinoma (HCC) 6 years previously. Although she exhibited a gradual increase in serum levels of α-fetoprotein and PIVKA-II starting 2 years before admission, no tumors were detected in the liver by abdominal ultrasonography and computed tomography. On admission, contrast-enhanced computed tomography revealed not only the colon cancer but also a tumor adjacent to the cecum. Both tumors were successfully removed by surgery and a pathological analysis revealed that the cecum tumor was poorly-differentiated HCC. The serum levels of α-fetoprotein and PIVKA-II declined markedly after the operation and no masses considered as peritoneal metastasis have been detected to date. This is the first report of the simultaneous resection of disseminated HCC and colon cancer.