Factors captured in a geriatric assessment can predict morbidity and mortality in older adults, but are not routinely measured in cancer clinical trials. This study evaluated the implementation of a geriatric assessment tool in the cooperative group setting. Patients age ≥ 65 with cancer, who enrolled on cooperative group cancer trials, were eligible to enroll on Cancer and Leukemia Group B (CALGB) 360401. They completed a geriatric assessment tool before initiation of protocol therapy, consisting of valid and reliable geriatric assessment measures which are primarily self-administered and require minimal resources and time by healthcare providers. The assessment measures functional status, comorbidity, cognitive function, psychological state, social support, and nutritional status. The protocol specified criteria for incorporation of the tool in future cooperative group trials was based on the time to completion and percent of patients who could complete their portion without assistance. Patient satisfaction with the tool was captured. Of the 93 patients who enrolled in this study, five (5%) met criteria for cognitive impairment and three did not complete the cognitive screen, leaving 85 assessable patients (median age, 72 years). The median time to complete the geriatric assessment tool was 22 minutes, 87% of patients (n = 74) completed their portion without assistance, 92% (n = 78) were satisfied with the questionnaire length, 95% (n = 81) reported no difficult questions, and 96% (n = 82) reported no upsetting questions. One hundred percent of health care professionals completed their portion. This brief, primarily self-administered geriatric assessment tool met the protocol specified criteria for inclusion in future cooperative group clinical trials.