We treated two patients in whom irinotecan (CPT-11)+cisplatin (CDDP) and irradiation showed efficacy against brain metastases of gastric cancer. CPT-11 and CDDP were administered on days 1 and 15 of a 28-day cycle at 60 mg/m(2) and 30 mg/m(2), respectively. The first patient was a 63-year-old man,who complained of headache and weakness. In March 2003, he was diagnosed as having Stage IV gastric cancer with peritoneal dissemination (T3, Nx, P1) and underwent total gastrectomy with D1 dissection. Chemotherapy with S-1 was continued after surgery. Two years and two months later, a metastatic tumor was found in the upper lobe of the right lung. The protocol was changed to S-1+CDDP, but progression of his disease occurred. The weekly paclitaxel (PTX) therapy was tried instead. Seven months later, he developed headache and weakness, and multiple brain metastases were diagnosed by CT scanning. We performed total brain irradiation (30 Gy) and started CPT-11+CDDP therapy, which was continued on a fortnightly basis at 60 mg/m(2) and 30 mg/m(2), respectively. The brain metastases regressed (PR), and this therapy led to a marked improvement in his quality of life. The second patient was a 78-year-old man, who complained of weakness of the lower extremities and dizziness. In November 2003, he was diagnosed as having stage IB gastric cancer (T2 (ss), N0, P0), and underwent total gastrectomy and splenectomy with D2 dissection. One year and four months later, local recurrence at the anastomosis was detected, as well as a metastatic tumor in the right lung. S-1, S-1+CDDP, and weekly PTX therapy were all tried. One year later, the patient was admitted with weakness and dizziness,and brain metastases were detected by CT scanning. We then performed Cyber Knife treatment and administered CPT-11+CDDP. As a result, his brain metastases partially regressed (PR).