The prevalence of multimorbidity and frailty is increasing in tandem with age. While many conditions in later life are amenable to surgical intervention, the decision to operate in older adults requires careful consideration and discussion based on overall risk–benefit assessment and individual goals and preferences. A tailored approach to preoperative, intraoperative and postoperative care is required for frail older patients who may have unique vulnerabilities and complex health profiles. Comprehensive geriatric assessment (CGA) models provide an essential framework for evaluating and optimising the health of these patients, which can lead to improved surgical outcomes. This chapter explores key geriatric assessment models and their application in the surgical care of frail older adults.