Brief dementia screening instruments, or mental status tests are frequently used to screen for cognitive impairment. We discuss the strengths and weaknesses of existing mental status tests in dementia screening in general. Most screening instruments that are used in clinical practice are developed to detect dementia compatible with Alzheimer's disease, and their value in detecting dementia after stroke is less well known. A stroke may cause both cortical and subcortical deficits, and the clinical expression of post-stroke dementia is different from that of Alzheimer's disease. Existing brief mental status tests have limited value in this patient group because they tend to ignore specific problems which may occur in stroke patients. Some expanded screening instruments, like the CAMCOG, are more useful and have additional diagnostic value. With the growing interest in research for vascular factors in dementia over the past years, however, a specific screening instrument for post-stroke dementia would be a valuable contribution.