PURPOSE Comprehensive geriatric assessment (CGA) is a multidimensional method used by geriatricians and oncologists to detect and evaluate multiple age-related problems and to plan and coordinate interventions. Because its main drawback is the time required, efforts have been made to evaluate screening instruments suitable for preliminarily assessing elderly patients. The main aim of this study was to establish the accuracy of the Vulnerable Elders Survey-13 (VES-13) in predicting the presence of abnormalities revealed by CGA. PATIENTS AND METHODS Patients age > or = 70 years with a histologically or cytologically confirmed diagnosis of a solid or hematologic tumor underwent both CGA and a VES-13 assessment, and the reliability and validity of VES-13 were analyzed. Results Fifty-three percent of the 419 elderly patients with cancer (mean age, 76.8 years) were vulnerable on VES-13; the rates of disabilities on CGA and activities of daily living (ADLs)/instrumental activities of daily living (IADLs) scales were 30% and 25%, respectively. The sensitivity and specificity of VES-13 were 87% and 62%, respectively, versus CGA and 90% and 70%, respectively, versus ADL/IADL scales. CONCLUSIONS On the basis of our data, VES-13 is highly predictive of impaired functional status and can thus be considered a useful preliminary means of assessing older patients with cancer before undertaking a full CGA.