OBJECTIVE:To compare the Short Test of Mental Status (STMS) with the Montreal Cognitive Assessment (MoCA) for predicting and detecting mild cognitive impairment (MCI). PARTICIPANTS AND METHODS:Participants from the community-based Mayo Clinic Study of Aging (MCSA) (November 24, 2010, through May 19, 2012) and an academic referral Alzheimer's Disease Research Center (ADRC) (March 16, 2015, through September 5, 2018) were analyzed. All participants were evaluated using a standardized neuropsychological battery, and a multidisciplinary consensus diagnosis was assigned. The MCSA and ADRC samples included 313 and 106 stable cognitively normal (CN) participants, 72 and 8 CN participants at baseline who developed incident MCI or dementia, 114 and 96 participants with prevalent MCI, and 25 and 132 participants with dementia, respectively. RESULTS:There were no statistically significant differences between the 2 tests in 6 of 7 diagnostic comparisons across academic referral and community populations. The STMS had a better area under the curve (0.90; 95% CI, 0.87-0.93) for differentiating prevalent MCI from CN participants in the MCSA cohort compared with the MoCA cohort (0.85; 95% CI, 0.81-0.89; P=.01). In addition, 53% of the stable CN participants (222 of 419) scored less than 26 on the MoCA, with specificity of 47% for diagnosing prevalent MCI. CONCLUSION:We provide evidence that the STMS performs similarly to the MoCA in a variety of settings and neurodegenerative syndromes. These results suggest that the current recommended MoCA cutoff score may be overly sensitive, consistent with previous studies. We also provide a conversion table for comparing the 2 cognitive tests.