Use of reliable screening and diagnostic tests for assessment of cognitive abilities in neurological patients is rapidly increasing in clinical practice. This is due to the increase in the prevalence of dementias and the raised awareness of cognitive impairment in neurological disorders. Two well-known bedside screening tests for dementias among the English-speaking population are the Mini Mental State Examination (MMSE) and Addenbrooke's Cognitive Examination (ACE). However, such tests have not been developed for the Persian-speaking population, which is estimated at 120 million worldwide. In this study we developed the Persian ACE and MMSE, adopted from the English version. We also assessed the sensitivity and specificity of these tests in the identification of Alzheimer's disease (AD) and mild cognitive impairment (MCI). We found that the Persian ACE at a cutoff point of 84, has a sensitivity of 93% and a specificity of 91% in discriminating MCI from a normal population; at 78, the test has a sensitivity of 73% and a specificity of 93% in differentiating MCI from AD, and at a similar cutoff point has a sensitivity of 100% and specificity of 96% in discriminating AD from a normal population. We conclude that the Persian ACE is a valuable tool in clinical practice in the Persian-speaking population.