The comprehensive geriatric assessment (CGA) is a versatile tool for the care of the older person diagnosed with cancer. The purpose of this article is to detail how a CGA can be tailored to Ambulatory Geriatric Oncology Programs (AGOPs) in academic cancer centers and to community oncology practices with varying levels of resources. The Society for International Oncology in Geriatrics (SIOG) recommends CGA as a foundation for treatment planning and decision-making for the older person receiving care for a malignancy. A CGA is often administered by a multidisciplinary team (MDT) composed of professionals who provide geriatric-focused cancer care. CGA can be used as a one-time consult for surgery, chemotherapy, or radiation therapy providers to predict treatment tolerance or as an ongoing part of patient care to manage malignant and non-malignant issues. Administrative support and proactive infrastructure planning to address scheduling, referrals, and provider communication are critical to the effectiveness of the CGA.