As few as 50% of dementia cases are diagnosed by physicians. This study investigated how primary care physicians assess patients for dementia and identified barriers to dementia diagnosis in the primary care setting. Seventy-eight physicians in three geographic areas participated in 18 focus groups. Barriers identified included: (a) the failure to recognize and respond to symptoms of dementia; (b) a perceived lack of need to determine a specific diagnosis; (c) limited time; and (d) negative attitudes toward the importance of assessment and diagnosis. These barriers keep physicians from diagnosing dementia and, consequently, from offering concrete help for patients experiencing symptoms of dementia or for the families who care for them.