•Screening for amnestic disorder must differentiate changes associated with normal aging.•Using an odorant identification test, the authors identified specific odorants which best differentiate amnestic disorder from normal aging. The identified odorants were validated with performance on neuropsychological testing and prediction of conversion from amnestic mild cognitive impairment to Alzheimer disease.•Olfactory identification impairment was associated with poor performance in numerous cognitive domains and was predictive of progression of mild cognitive impairment.•Olfactory identification deficit can be utilized for risk stratification of progression from amnestic mild cognitive impairment (aMCI) to Alzheimer disease (AD) and to enrich clinical trials of potential disease-modifying therapies for converters.