The Alzheimer Questionnaire (AQ) has been established as a valid and accurate informant-based screening questionnaire for Alzheimer disease and amnestic mild cognitive impairment. Although the AQ’s validity and diagnostic accuracy has been established, its performance in comparison with other instruments has not. Thirty-nine amnestic mild cognitive impairment cases and 34 Alzheimer disease cases were matched on the basis of age, education, and sex to 73 cognitively normal individuals. The sample had a mean age of 82.54±7.77 years and a mean education level of 14.61±2.61 years. The diagnostic accuracy of the CDR Sum of Boxes, Mini Mental State Exam (MMSE), and Montreal Cognitive Assessment (MoCA) were compared with the AQ. The AQ correlated strongly with the CDR Sum of Boxes (r=0.79) and demonstrated similar diagnostic accuracy with the MoCA and MMSE. These results suggest that the AQ is comparable with other established informant-based and patient-based measures.