A 60-year-old female was diagnosed as advanced gastric cancer with multiple bone, neck and mediastinal lymph node metastases. As a primary chemotherapy, she was treated with S-1(50 m g/body, twice daily for 4 weeks, followed by a 2- week rest). After 3 courses of S-1, she developed a disease progression with pulmonary lymphangitic carcinomatosis and disseminated intravascular coagulation(DIC). Therefore, she received second-line chemotherapy of irinotecan(CPT-11 150 mg/m2, biweekly). Within 3 weeks of starting the treatment, the clinical and laboratory signs of DIC were dramatically resolved. There have been no previous reports of irinotecan alone showing such remarkable effectiveness in a patient with 5- FU-resistant gastric cancer with DIC.