Background/Aims: Only a limited number of cognitive screening tools are available for the Persian-speaking population, and we sought to translate and validate the Neuropsychiatry Unit Cognitive Assessment Tool (NUCOG), a multidimensional cognitive screening tool. Methods: We used multiple language specialists to translate and then back-translate the NUCOG, and administered the Persian language NUCOG and Mini-Mental State Examination (MMSE) to 184 individuals: 60 controls and 124 patients, 33 of whom had dementia, 30 non-dementing neurological disorders and 61 a psychiatric illness. Results: The NUCOG outperformed the MMSE in differentiating the patient groups and controls. The ‘profile’ across the 5 NUCOG domains differentiated dementia subgroups such as senile dementia of the Alzheimer type (SDAT), frontotemporal dementia and mild cognitive impairment (MCI). Psychiatric patients with psychosis and posttraumatic stress disorder were more impaired than patients with affective disorders. The NUCOG reliably differentiated controls from patients with MCI (at 86.5/100, sensitivity of 83.3% and specificity of 87.5%) and SDAT (at 75/100, sensitivity and specificity of 100%) patients from controls. Conclusions: The Persian language NUCOG appears to perform strongly in an unselected population, reliably differentiating patients with dementia from controls, and detecting cognitive impairment in a range of clinical disorders.