Lung cancer is the commonest malignancy worldwide and the leading cause of cancer death. Half of patients with lung cancer present with advanced disease. The number of systemic therapies including immunotherapy and targeted treatment are rapidly increasing. Despite this, the outcomes for many patients with locally advanced and advanced lung cancer are poor, as many patients are too unwell for treatment. One of the reasons patients with Non-Small Cell Lung Cancer are not fit for treatment is cancer cachexia, which is common (upto 75% of patients) in this group. This metabolic syndrome presents clinically as weight loss (muscle +/– fat), decreased physical function (patients less active) and anorexia on a background of systemic inflammation. Currently there is not an optimal management pathway for these patients, however, there is emerging data that multi-modal intervention including nutritional support, physical training and pharmacological therapy may have a role in treating cachexia. This review discusses assessment and intervention in cancer cachexia.