Cachexia is well known to be a complication with malignant disease. The frequency of cancer-associated cachexia is different among various type of cancer, and relatively high in pancreas cancer, gastric cancer or lung cancer. The typical symptoms with cancer-associated cachexia includes body weight loss, appetite loss and general fatigue. In 2011, EPCRC published the consensus report of definition for cancer-associated cachexia in 2011, and the diagnostic criteria based on body weight loss is used widely. Although the systemic inflammation complicated with cancer plays an important role for cachexia development, basic research has clarified that cancer promotes cachexia directly using proteolysis inducing factor, lipid mobilizing factor and others. Recently, anamorelin, ghrelin mimics gathers attention as a treatment drug for cancer-associated cachexia. Clinical trials confirmed that anamorelin increased the lean body mass in cancer patients probably due to improve the appetite and protein anabolism. Treatment strategy for cancer-associated cachexia needs the comprehensive approach with nutritional and exercise therapy in addition with anti-cachexia drug.