Validated diagnostic scales for dementia in Arabic are still scarce. The aim of this study is to construct a standardized dementia scale for dementia diagnosis among the Arabic-speaking population.Construction of the Dementia Arabic Scale (DAS) was done, followed by evaluation of content validity. A pilot study was done to ascertain feasibility and language clarity used in the scale. Patients diagnosed to have major neurocognitive disorder according to DSM-V criteria and control group were subjected to DAS, mini-mental state examination (MMSE) and Cognitive Abilities Screening Instrument (CASI). Finally, standardization of the scale and estimation of cutoff point, sensitivity, specificity, positive predictive value and negative predictive value of the newly constructed scale (DAS) were done.There is significant correlation between DAS and both MMSE and CASI on Pearson's correlation study. The internal consistency of the DAS scale was good, with Cronbach's alpha correlation coefficient of 0.88. At cut-off ≤95 for literate, and ≤68 for illiterate, the sensitivity of the DAS scale was 100%, 87% for literate and illiterate, respectively, while specificity was 84%, 96% respectively, with an area under the receiver operating characteristic curve of (AUC) 0.96.The DAS scale is an acceptable, reliable and valid scale for the diagnosis of dementia in Arabic-speaking countries.