Objectives: To assess the validity of a simple questionnaire to identify outpatient elderly persons at high risk of functional decline and who are likely to benefit from a comprehensive geriatric assessment.Methods: A comparison was made between results of a 23-item screening questionnaire based on activities of daily living and data from an overall clinical geriatric evaluation (standard criterion). A total of 300 people aged 65 years or older attending three general practices were screened for functional status in office settings. Patients completed the 23-item questionnaire and underwent a geriatric evaluation by a family physician who was unaware of the results of the screening instrument. A stepwise logistic regression analysis showed that six items were independent predictors of functional disability. The discriminant ability of the questionnaire scores for the diagnosis of functional disability was evaluated using the receiver operating characteristics (ROC) curves. Interobserver reliability of the questionnaire was also assessed.Results: When used as an exclusion test, the 23 items of the questionnaire showed a sensitivity of 88% and a specificity of 40%, with 50% sensitivity and 89% specificity when used as a confirmation test. The six-item questionnaire had 81% sensitivity and 56% specificity as an exclusion test and 58% sensitivity and 89% specificity as a confirmation test. The use of the five-item plus age questionnaire provided similar results. Test-retest reliability for the different cut-off points varied between 0.55 and 0.76.Conclusions: This six-item instrument showed an acceptable validity index to facilitate the implementation of geriatric evaluation and management programmes in primary healthcare centres.