We report a case of pseudomyxoma peritonei caused by carcinoma of the appendix, which was successfully treated with multidisciplinary treatment including modified FOLFOX6 regimen. A 45-year-old man was diagnosed as having peritoneal dissemination associated with cancer of the cecum or appendix. Seven cycles of mFOLFOX6 treatment resulted in a marked decrease in ascites and serum levels of carcinoembryonic antigen and carbohydrate antigen 19-9. At laparotomy, a diagnosis of pseudomyxoma peritonei caused by cancer of the appendix was made. Intraperitoneal lavarge with 10,000 mL 5% glucose was performed after right hemicolectomy, omentectomy and removed of mucinous peritoneal nodules. Intraperitoneal chemotherapy comprised of 3000 mL low molecule dextran and 80 mg cisplatin was added on postoperative days 7 and 14. Modified FOLFOX6 regimen was started again two months postoperatively and reached 28 cycles. The patient does not show any sign of recurrence 12 months postoperatively.