peer reviewed ; OBJECTIVES: The aim of this study is to identify treating physicians' general experiences and expectations regarding geriatric assessment (GA) in older patients with cancer. MATERIALS AND METHODS: A survey was carried out in 9 Belgian hospitals, which participated in a national GA implementation project focusing on older patients with cancer. A newly developed questionnaire was completed by their treating physicians. Data collection comprised of reviewing hospital data, general respondent data, and treating physicians' general experiences and expectations regarding GA. Descriptive statistics were calculated. RESULTS: Eighty-two physicians from 9 hospitals participated. The GA team composition can vary substantially, with a nurse as core member. Ideally, all older patients with cancer in whom a treatment decision is necessary, should benefit from the GA. Nearly all GA domains are reported as very important. Availability of GA results can be improved. Treating physicians want geriatricians to coordinate geriatric recommendations related to the identified GA problems, and expect from trained healthcare workers (THCWs) to collect GA data, to report GA results, and to follow-up the implementation of geriatric recommendations. CONCLUSION: This study identifies relevant information for improving the implementation of GA in older patients with cancer in Belgium and reveals priorities for a THCW from the treating physician's point of view. To increase the effectiveness of GA, further efforts are needed to improve the implementation of geriatric recommendations.