Chylothorax is a form of pleural effusion rarely caused by metastasis of solid tumors. Because chylothorax causes complaints by local compression of the lung, as well as weight loss resulting from loss of triglycerides, it needs thorough investigation. We present the case of gastric carcinoma presenting with a chylothorax and unilateral lymph edema. Although rare, the differential diagnosis of chylothorax should include gastric cancer even in the absence of upper abdominal complaints.