Sixty percent of all cancer occurrences and seventy percent of cancer mortalities occur in people over the age of 65. As the population ages, there is an emerging need to develop a means for oncologists to characterize the "functional age" of older patients with cancer in order to tailor treatment decisions and stratify outcomes based on factors other than chronological age and to develop interventions to optimize cancer treatment. In this paper, we discuss the formulation of a geriatric assessment for older patients with cancer. The measures included in this assessment were chosen based on their validity, reliability, brevity, adaptability for self-administration, and ability to prognosticate risk for morbidity or mortality in an older patient. The proposed geriatric assessment covers the essential domains of assessment predictive of survival in the geriatric population, is primarily self-administered, and limited personnel time is required. Our eventual goal is to determine if this geriatric assessment measure can identify factors independent of age that predict cancer treatment morbidity and mortality and result in rationale interventions to optimize oncologic care.