Objective: To investigate the prevalence and risk factors of post-stroke cognitive impairment (PSCI) in patients with ischemic stroke at community health service stations. Methods: Five community health service stations were selected from 5 urban areas of Beijing, and a study was performed in patients with first or recurrent attack of ischemic stroke at the community health service stations from January 2003 to December 2004. The mini mental state examination (MMSE) was used to assess the cognitive function of the patients, and the data about the onset of stroke and the risk factors of stroke were collected. Results: A total of 993 patients were completed the MMSE evaluation, the incidence of PSCI was 7.9% (78/993). The prevalence of PSCI within 6 months, 7-12 months, and 12 months after onset of stroke were 8.5%, 10.1%, and 4.9%, respectively. The prevalence of PSCI in patients under 60 years of age was 3.9%, and the prevalence in 60-65, 65-70, and ≥70 year groups were 5.1%, 8.1%, and 11.4% respectively (χ2 trend test = 12.521, P < 0.0001). The prevalence of PSCI was varied with the educational level of the patients, in patients with college graduates was 3.6%, in patients with middle, primary school education and illiterate were 1.72, 3.94, and 4.04 times of the college graduates (χ2 trend test = 13.694, P < 0.0001). The impact factors of PSCI were the multi-focal stroke, depressive state, activities of daily living handicap, and non-lacunar infarction of which, the first three were the independent risk factors for PSCI. Conclusion: PSCI in patients with ischemic stroke is associated with a variety of factors, such as the course of disease, educational level, age of disease onset etc. The multi-focus stroke, depressive state, and activities of daily living handicap are the independent risk factors for PSCI.