Background: Despite the growing burden of cancer in older adults in Mexico, it is unknown how many cancer care providers in Mexico use information obtained through a geriatric assessment (GA) and/or geriatric oncology principles in their everyday clinical practice. Methods: We administered a cross-sectional survey to oncology providers in Mexico via the Mexican Society of Oncology mailing list (n = 1240). The survey included questions on demographics, awareness about geriatric oncology principles, and the use of the GA and other geriatric clinical tools. The primary outcome was to estimate the proportion of providers using GA tools through the question: “For your patients ≥65 years, do you perform a multidimensional geriatric assessment using validated tools?”. We hypothesized that ≤10% of respondents would give a positive answer. We used descriptive statistics and X2 tests to compare groups of respondents. Results: We obtained 196 answers (response rate 15.8%). 121 (62%) respondents were male; median age 42. 98 (50%) were surgical oncologists, 59 (30%) medical oncologists, and 38 (19%) radiation oncologists. Median time in practice was 8 years, with 39% practicing in Mexico City. A third had their practice at a public institution, 26% at a private institution, and 38% in both. The proportion of patients aged 65-79 and ≥80 seen on an average clinic day by the respondents was 30% and 10%, respectively. 121 (62%) reported having a geriatrician available at their practice site. 37 respondents (19%) reported using validated GA tools to evaluate older adults with cancer in their practice. The proportion of respondents who evaluated each GA domain is shown in Table 1. Male respondents (p=0.03), medical oncologists (p<0.01), and those with a less busy practice (≤10 patients/day) (p=0.01) were more likely to use validated tools to perform a GA. Regarding barriers for implementing GA, 37% reported lack of time, 49% lack of qualified personnel, 44% lack of knowledge of geriatric tools, 6% patient unwillingness to undergo a GA, and 8% prohibitive cost. Only 17 (9%) thought that information obtained through a GA would not lead to practice changes. Conclusions: According to our survey, the proportion of Mexican oncology providers using validated tools to perform a GA is 19%, which is higher than expected. Some GA domains, such as comorbidity and functional status, were commonly assessed, while others, such as fall history, were seldom evaluated. Common barriers for GA implementation were lack of qualified personnel and of knowledge about geriatric tools. We plan to further explore these barriers and potential facilitators through focused interviews in order to guide future interventions.