Chylothorax has been reported to be caused by accidental injuries in half of all cases in Japan, and < 10% of these cases have been associated with malignant tumors, including lymphoma. Chylothorax is a rare complication of gastric carcinoma. We successfully treated a 58-year-old man with gastric carcinoma, chylothorax, and ascites using a combination of talc pleurodesis and a lipid-limited diet. Case: A 58-year-old man with advanced stage of poorly differentiated gastric adenocarcinoma presented to our hospital with complaints of shortness of breath. Whole-body computerized tomographic images suggested massive pleural effusion and ascites. Examination of pleural fluid and ascites revealed elevated serum triacylglycerol levels of up to 913mg/dL with numerous free-floating cancer cells. Malignant chylothorax was diagnosed. A lipid-limited diet and octreotide were started, followed by talc pleurodesis for pleural effusion. The patient with controlled pleurisy died of gastric cancer on day 55 after pleurodesis.