Purpose: In older adults, falls are a common cause of functional decline, institutionalization, and reduced quality of life. This study (1) investigates the prevalence of falls in a large sample of community-dwelling older adults with a cancer diagnosis and (2) evaluates the association of falls with domains of comprehensive geriatric assessment (CGA) that pertain to falls risk. Methods: Patients completed a CGA that includes a self-reported measure of number of falls in the past 6 months. Summary statistics are used to describe prevalence of falls and associations with hypothesized risk factors using Fisher’s exact tests and multivariable logistic regression. Results: A total of 1172 patients were enrolled, mean age 73 (65–99), 74 % female, and 89 % Caucasian. Two hundred fifty-six (22 %) reported one or more falls within the last 6 months. Patients with at least one instrumental activities of daily living (IADL) or physical function deficit had more falls as compared those with no deficits identified (p ≤ 0.001). The number of daily medications, comorbidities, Timed Up and Go score >14 s, and poor vision were also associated with increased falls (p ≤ 0.001). Reduced physical function, poor vision, and low performance status had the highest adjusted odds ratio (3.6, 3.4, and 3.0, respectively) for falls. Conclusions: There is a high prevalence of falls in community-dwelling older patients with a cancer diagnosis. Falls are significantly associated with several measures of geriatric assessment including IADL, physical function, comorbidities, medications, and vision. Timely identification and management of risk factors for falls are important considerations in the care of older cancer patients.