Cancer cachexia is a syndrome characterized by weight loss with accompanying loss of muscle and/or fat mass and leads to impaired patient function and physical performance and is associated with a poor prognosis. It is prevalent in older adults with cancer; age-associated physiologic muscle wasting and weakness, also known as sarcopenia, can compound deficits associated with cancer cachexia in older adults and makes studying this condition more complex in this population. Multiple measurement options are available to assess the older patient with cancer and cachexia and/or sarcopenia including anthropometric measures, imaging modalities such as Dual X-ray absorptiometry (DEXA) and Computed Tomography (CT), muscular strength and physical performance testing, and patient-reported outcomes (PROs). A geriatric assessment (GA) is a useful tool when studying the older patient with cachexia given its comprehensive ability to capture aging-sensitive PROs. Interventions focused on nutrition and increasing physical activity may improve outcomes in older adults with cachexia. Efforts to develop targeted pharmacologic therapies with cachexia have not been successful thus far. Formal treatment guidelines, an updated consensus definition for cancer cachexia and the development of a widely adapted assessment tool, much like the GA utilized in geriatric oncology, could help advance the field of cancer cachexia over the next decade.