Intraperitoneal chemotherapy, in which an anticancer drug is administered directly into the abdominal cavity through an intraperitoneal access port(IP port), is one of the treatment options for advanced gastric cancer with peritoneal metastasis. Herein, we report a case of sheath-like obstruction of the entire catheter of the IP port due to tissue reaction within a short period of time after IP port implantation. The case was a 35-year-old woman with advanced type 4 gastric cancer with peritoneal dissemination. The IP port was placed and intravenous and intraperitoneal chemotherapy using S-1 plus paclitaxel was started. However, in the middle of the second course, the entire catheter was covered with a fibrous capsule and a sheath-like obstruction occurred, so the IP port was removed and a new IP port was reinserted. One of the IP port troubles is obstruction, but such short-term and special obstruction is rare, and the cause is considered to be a foreign body reaction of the catheter.