Objectives: The present study was carried out with the aim of assessing the psychometric properties of “Neuro-psychiatry Unit Cognitive Assessment Tool” (NUCOG) in patients with dementia. Method: In a descriptive-analytical study, patients presenting to Noor Hospital Neuropsychiatric Clinic and the Neurology Department of Ayatollah Kashani Hospital in Isfahan in autumn 2008 were evaluated and 33 individuals with dementia were selected using convenience sampling. The Mini-Mental State Examination (MMSE) and NUCOG were administered to the patients. Data were analyzed using descriptive statistics, Pearson correlation coefficient, Chi² test, and Cronbach’s alpha. Results: Content validity of NUCOG was confirmed. The internal consistency of the NUCOG by Cronbach's alpha was 0.919.  The convergent validity of the MMSE and the NUCOG was 0.922 (p<0.001). There was no significant correlation between age and education, and NUCOG total scores. Conclusion: The Persian version of the NUCOG is a valid and reliable tool for screening patients with dementia in clinical psychiatric settings.