Background: GO evaluations may lead to improvements in the care of older adults with cancer, but their effect on Tx decisions in everyday clinical practice needs further research. Our goal was to describe the effect of GO evaluations on Tx decisions in the first GO clinic implemented in Mexico. Methods: The records of 173 pts aged ≥65 years (y) referred to our GO Clinic before active Tx initiation from 05/15 to 10/17 were reviewed. Pts were screened with a validated tool (G8; Soubeyran et al, 2011); those deemed vulnerable (score ≤14) underwent a full geriatric assessment; and Tx recommendations were sent to the treating oncologist. We measured the proportion of patients in which there was agreement between GO recommendations and final Tx decisions, and assessed whether agreement increased in cases in which the treating oncologist’s notes mentioned the GO evaluation. Results: Median age was 79 y (range 64-97). 37% of pts had genitourinary and 32% gastrointestinal malignancies; 42% were stage IV. Proposed Tx before GO evaluation included palliative chemotherapy (CT) (32%), curative surgery/radiotherapy (31%), and neo/adjuvant CT (19%). A recommendation to administer standard Tx was made in 47% of cases, less intensive Tx in 32%, and best supportive care (BSC) in 20%. The treating oncologist’s final Tx decision matched the GO recommendation for 81% of pts, and GO recommendations were mentioned in the treating oncologist’s notes in 62% of cases. Agreement between the treating oncologist & GO clinic was higher when BSC was recommended (94%), followed by standard Tx (77%), and less intensive Tx (75%). Agreement between the treating oncologist & GO clinic was 84% when the GO evaluation was mentioned, compared to 75% when it wasn't (p = 0.16). In pts for which less intensive Tx was recommended (n = 56), agreement was 84% when the GO evaluation was mentioned, compared with 56% when it wasn't (p = 0.04). Conclusions: Agreement between GO recommendations and final Tx decisions was high, especially for cases in which BSC was recommended. Including GO evaluations in everyday clinical practice may provide useful information to guide oncologists caring for older pts, particularly when considering less intensive therapy.