Introduction: The age of the population in Saudi Arabia is shifting toward elderly, which can lead to an increased risk of mild cognitive impairment (MCI) and dementia. Objective: The aim of this study is to determine the prevalence of cognitive impairment (MCI and dementia) among elderly patients in a community-based setting in Riyadh, Saudi Arabia. Methods: In this cross-sectional study, we included patients aged 60 years and above who were seen in the Family Medicine Clinics affiliated with King Faisal Specialist Hospital and Research Centre. Patients with delirium, active depression, and patients with a history of severe head trauma in the past 3 months were excluded. Patients were interviewed during their regular visit by a trained physician to collect demographic data and to administer the validated Arabic version of the Montreal Cognitive Assessment (MoCA) test. Results: One hundred seventy-one Saudi patients were recruited based on a calculated sample size for the aim of this study. The mean age of included sample was 67 ± 6 years. The prevalence of cognitive impairment was 45%. The prevalence of MCI was 38.6% and the prevalence of dementia was 6.4%. Age, low level of education, hypertension, and cardiovascular disease were risk factors for cognitive impairment. Conclusion: Prevalence of MCI and dementia in Saudi Arabia using MoCA were in the upper range compared to developed and developing countries. The high rate of risk factors for cognitive impairment in Saudi Arabia is contributing to this finding.