To examine the psychometric properties of the 15-item Geriatric Depression Scale (GDS-15), a brief depression screening measure. Cross-sectional. Nineteen counties in western New York, West Virginia, and Ohio. Nine hundred sixty functionally impaired, cognitively intact, community-dwelling primary care patients aged 65 and older. The GDS-15, major depression as measured using the Mini-International Neuropsychiatric Interview, depressed mood, life satisfaction, suicidal ideation, and reported suicide attempts. Exploratory factor analyses suggested a two-factor structure for the GDS-15 in this category of patients, with component subscales assessing depression and positive affect. Cronbach alpha coefficients provide evidence for moderate, although acceptable, internal consistency reliability. Significant associations between the GDS-15 and measures of depressed mood, life satisfaction, and suicidal ideation demonstrated construct validity, whereas acceptable sensitivity and specificity to discriminate between depressed and nondepressed patients demonstrated criterion validity. Internal consistency reliability and construct validity did not differ significantly between patients with low and high functional impairment. A significant weakness of the scale is its low correlation with suicide attempt status. In general, this study provides evidence of impressive psychometric properties of the GDS-15 when administered to a sample of functionally impaired, cognitively intact, community-dwelling primary care patients.