The Brief Cognitive Assessment Tool (BCAT) is a new screening measure for cognitive dysfunction that emphasizes contextual memory and executive control functions. A total of 104 older adults referred for neuropsychological evaluation were recruited from assisted-living facilities. Psychometric analyses confirmed strong evidence for reliability, construct validity, and predictive validity. The BCAT's utility for identifying dementia versus mild cognitive impairment was excellent, with a sensitivity of .99, a specificity of .77, and an area under the receiver-operating characteristic (ROC) curve of .95. Executive control, contextual memory, and attentional capacity items were the best predictors of diagnostic category and of instrumental activities of daily living.