As the global population ages, so does the number of older people being diagnosed, treated and surviving cancer. Challenges to providing appropriate healthcare management stem from the heterogeneity common in this population. Although malnutrition is highly prevalent in older people with cancer, ranging between 30 % and 80 % according to some analyses, is associated with frailty, and has been shown to be a major risk factor for poor treatment response and worse overall survival, addressing nutrition status is not always a priority among oncology healthcare providers. Evaluation of nutritional status is a two-step process: screening identifies risk factors for reduced nutritional intake and deficits that require more in-depth assessment. Screening activities can be as simple as taking weight and BMI measurements or using short nutritional questionnaires and asking the patient about unintentional weight loss to identify potential nutritional risk. Using geriatric assessment, deficits in the nutritional domain as well as in others reveal potentially reversible geriatric and medical problems to guide specific therapeutic interventions. The authors of this paper are experts in the fields of geriatric medicine, oncology, and nutrition science and believe that there is not only substantial evidence to support regularly performing screening and assessment of nutritional status in older patients with cancer, but that these measures lead to the planning and implementation of patient-centered approaches to nutrition management and thus enhanced geriatric-oncology care. This paper presents rationale for systematic nutrition screening and assessment in older adults with cancer.