We report 2 successful cases treated with trans-catheter arterial embolization(TAE)for hemorrhagic shock due to pseudoaneurysm rupture at the primary tumor site in advanced colorectal cancer. Case 1: A 73-year-old female underwent Hartmann surgery at another hospital for rectal perforation and peritonitis. Six months later, she had a massive bloody stool and was transferred to our hospital. She was diagnosed with bleeding from advanced rectal cancer that remained following the first surgery. Contrast computed tomography(CT)showed that a branch of the superior rectal artery(SRA)developed an aneurysm at the primary tumor site, and TAE was performed to stop bleeding on hospital day 3. Case 2: A 79-year-old male with type 2 sigmoid colon cancer and simultaneous multiple liver metastases developed copious blood in the stool before primary tumor resection and was transferred to our hospital. Contrast CT showed that a branch of the SRA developed an aneurysm at the primary tumor site, and TAE was immediately performed to stop bleeding.