Clinicians should use a systematic approach to evaluating patients presenting with a concern for cognitive impairment. This approach includes interviewing a knowledgeable informant and performing a thorough mental status examination in order to determine the presence of functional impairments and the domains of cognition that are impaired. The results of this interview and examination determine the next steps of the diagnostic work-up. The pattern of cognitive impairment shapes the differential diagnosis. Treatment should address symptoms, and environmental, psychological, and behavioral interventions are essential.