Geriatric assessments have now been recommended as part of the standard evaluation of an older adult considering cancer therapy. While the need for a more in-depth performance status evaluation of an older person with cancer was identified over 20 years ago, completion of a comprehensive geriatric assessment (CGA) is time-consuming and not frequently performed as part of the standard assessment of older cancer patients. Evidence suggests that incorporating such an evaluation could be useful for potentially determining the patient's chemotherapy tolerability or treatment completion, toxicity, and survival, as age alone has been shown to poorly predict treatment failure, and performance status assessments commonly used in oncology practice may lack predictability. This review describes the increasing role of the CGA and geriatric assessment screening tools as well as their pertinent domains across various settings in the evaluation of the older adult with cancer who is considering cancer treatment.