Given the gradual improvement of living conditions and aging, dementia and related syndromes are becoming serious problems in the developing countries. A cross-sectional door to door type study in neighbourhood, was conducted from October 2008 to January 2009, in the general population in Bangui, order to help get a better understanding of the prevalence and risk factors of dementia among people over 65 living in the Central African capital. Of the 496 elderly respondents, 188 had cognitive disorders. After a neuropsychological examination, 40 of these subjects were diagnosed with dementia. The prevalence of dementia was 8.1% (IC 95% = [5.7-10.5]). The average age of subjects with dementia, ranging from 65 to 90 years, was 76.0 ± 7.1 years. There was a significant risk of developing dementia for an increase of ten years old (OR = 2.6, 95% CI [1.5 to 4.5]). The sex-ratio was 6/34. 82.5% of the demented had never attended school. 70.0% showed a state of malnutrition (BMI ≤ 18,5 kg/m(2)), significantly associated with dementia (OR = 3.3; IC 95% = [1.5-7.3]). The blood pressure was high in 67.5% of demented which is significantly associated with dementia (OR = 2.4; IC 95% = [1.1-5.4]). A recent change in financial status was a factor significantly associated with dementia (OR = 6.4; IC 95% = [1.8-22.5]). These results support the existence of dementia in urban Africa. The observed prevalence is close to those found in high-income countries. Further studies should be conducted which includes both the rural and urban Africa, to better understand the problem and solutions consider to comprehensive care and prevention axes adapted to our context.