A phase III clinical trial to evaluate the efficacy of combination chemotherapy with intraperitoneal administration of paclitaxel for gastric cancer with peritoneal metastasis has been ongoing in Japan. A male patient in his 50s who was diagnosed as having advanced gastric cancer with peritoneal metastasis was enrolled in this trial. The patient was assigned to receive a regimen of intravenous and intraperitoneal paclitaxel combined with S-1. Although an intraperitoneal access port had been implanted to provide access to the peritoneal cavity, tube obstruction occurred twice. Laparoscopic examination revealed that the tube in the abdominal cavity had been totally covered with the great omentum. Therefore, the intraperitoneal regimen was discontinued. Although intraperitoneal chemotherapy for the treatment of peritoneal dissemination in gastric cancer is promising, precaution should be taken to avoid tube obstruction, which is a complication of the intraperitoneal tube placement.