A 73-year-old man underwent partial hepatic resection (55) for metachronous metastatic liver tumor from cecal cancer in November 2005. A reservoir port for hepatic arterial infusion (HAI) adjuvant chemotherapy was placed in the right femoral artery and the HAI chemotherapy was carried out. In January 2006, he had swellings of the right lower leg and inguinal region and was admitted to our hospital for a hematoma in the site of the reservoir port and deep venous thrombosis. The swelling of the right lower leg went down with a bed rest in a couple of days. However, the hematoma of the reservoir port site was increased. The hematoma was removed and sutured to stop bleeding and then compression homeostasis was applied for a week. An enhanced pelvic CT scan showed a pseudoaneurysm in the femoral artery and an impending rupture was suspected. He was immediately referred to a vascular surgeon and underwent emergency surgery. Intraoperative angiography showed a pseudoaneurysm, 2.5 cm in diameter, in the femoral artery. An approximate 1 cm tear around the catheter insertion site was found and a primary suture was performed. A rapid diagnosis and treatment are required when a pseudoaneurysm is suspected during HAI chemotherapy.