A 64-year-old man complaining of anterior chest pain, weight loss, and neck tumors was found to have advanced gastric cancer with pleuritis carcinomatosa and multiple lymph node and bone metastases. The patient was treated with combination chemotherapy consisting of mitomycin C (MMC), tegafur (UFT), and lentinan, and then with MMC and 5-fluorouracil (5FU) instillation into the pleural spaces after pleural drainage. With these treatments, the primary tumors and cancerous ulcers of the stomach improved markedly, and the lymph node enlargement and pleural effusion disappeared completely. Afterwards pericardiac metastasis complicated by cardiac tamponade occurred, but repeated pericardiocentesis and administration of MMC into the pericardiac cavity effectively eliminated the effusion. These treatments appeared potentially useful for advanced gastric cancer with generalized metastases including pericardiac involvement. However, the patient died of cardiac tamponade with massive pericardiac bleeding, probably due to the repeated pericardiocentesis and/or the administration of anticancer drugs.