Abstract Geriatric assessment (GA) is used in oncology to identify deficits in older patients with cancer that may affect treatment choice. We examine GA in 550 patients with early breast cancer, including both younger (<65 years) and older women (aged 65 years or older), to assess the potential value of this tool in younger, presumed “healthier” patients. Although older women have more GA-identified deficits overall, younger patients are more anxious. Suboptimal physical function was problematic across the age spectrum. GA domains can identify major deficits in younger patients beyond those likely to be uncovered in routine investigation.