Objectives: Diagnostic pathways are limited. A validated instrument that can triage patients when they are suspected of mild dementia (MD) is necessary to optimise referrals. Method: The MoCA is validated for identifying MD and mild cognitive impairment (MCI) in a cohort of patients suspected of cognitive impairment (CI) after initial assessment in old age psychiatry. The reference standard was the consensus-based diagnoses for MD and MCI, adhering to the international criteria and using suspected patients, but without CI as comparisons (NoCI). Results: The mean MoCA scores differ significantly between the groups: 24(SE:.59) in NoCI, 21(SE:.31) in MCI and 16,7(SE:.45) in MD (p <.05). The AUC of MD against non-demented (MCI + NoCI) was 0.83(95%CI: 0.78–0.88) resulting in 90% sensitivity, 65% specificity, 50%PPV and 94%NPV at a “best” cutoff of <21 according the Youden index and respectively 0.77(95%CI: 0.69–0.85), 56%, 73%, 90%, 28% for CI (MD + MCI) against NoCI at <21. Conclusion: 90% of individuals with a MoCA of <21 will have CI (MD + MCI), while 94% with a MoCA of ≥21 will not have dementia. The MoCA can reduce referrals substantially (50%) by selecting who don’t need further work up in a memory clinic, even if they were suspected of CI after initial assessment.