This article provides clinical practice guidelines for primary care physicians in the assessment of dementia patients. Dementia is an acquired syndrome due to brain dysfunction, which is characterized by multiple cognitive deficits with consequent impairment in daily or occupational activities. Thus, the first and second steps in the clinical approach to dementia are the assessment of cognition and activities of daily living (ACL). The third step may be the evaluation of abnormal behaviors associated with dementia, since those symptoms are one of the main causes of caregivers' burden and can be controlled by drugs such as antipsychotics and antidepressants. Finally, as the fourth step of the evaluation, the underlying etiologies for dementia should be explored. This article describes the elemental methods of history taking and clinical examinations for dementia patients with emphasis on the assessment of 1) cognition, 2) ADL, 3) behaviors, and 4) differential diagnosis. The assessment will lead the clinician to accurate diagnosis and better management of dementia patients.