OBJECTIVES: No tools accurately discriminate between older patients who are fit and those who are frail to tolerate systemic palliative treatment. This study evaluates whether domains of geriatric assessment (GA) are associated with increased risk of chemotherapy intolerance in patients who were considered fit to start palliative chemotherapy after clinical evaluation by their treating clinician. MATERIALS AND METHODS: This prospective multicenter study included patients ≥70 years who started first line palliative systemic treatment. Before treatment initiation, patients completed GA including Activities of Daily Life (ADL), Instrumental Activities of Daily Life (IADL), Mini-Mental State Examination (MMSE), Mini Nutritional Assessment (MNA), Geriatric Depression Scale (GDS-15) and the Timed Up and Go Test (TUGT). Primary endpoint was treatment modification, defined as inability to complete the first three sessions of systemic treatment as planned. Secondary endpoint was treatment related toxicity ≥ grade 3 (CTCAE Version 4). The association between GA and endpoints were assessed using univariable and multivariable logistic regression analysis. RESULTS: Ninety-nine patients with median age of 77 (+/- 8) years underwent GA. 48% of the patients required treatment modification and grade 3 toxicity occurred in 53% of patients. One or more geriatric impairments were present in 71% of patients and 32% of patients were frail in two or more domains. Only TUGT was associated with treatment modifications (OR 2.9 [95% CI 1.3-6.5]) and grade 3 toxicities (OR 2.8 [95% CI 1.2-6.3]). CONCLUSION: Frailty was common in older patients who were considered fit to receive palliative chemotherapy. Treatment modification was necessary in half of the patients. Only TUGT was significantly associated with treatment modifications and grade 3 chemotherapy toxicities.