Background Increasing in the older people and a decline in mortality after stroke, the rate of poststroke cognitive decline has increased. The relationship between risk factors and post-stroke cognitive decline in dwelling old and oldest people who living in the community especially with asymptomatic stroke have to be elucidated. Therefore, the aim of this study is to investigate the association between stroke and cognitive decline during three years in community dwelling older and oldest people. Methods This study was longitudinal study with a 3-year follow-up in urban and rural areas of Japan. The participants were 1,333 community dwelling older and oldest people (70 years old = 675, 80 years old = 589, and 90 years old = 69). Data collected included basic data (age, sex, and history of stroke), vascular risk factors (hypertension, diabetes mellitus, dyslipidemia, atrial fibrillation, and current smoking), and social factors (educational level, frequency of going outdoors, and long-term care (LTC) service used). The Japanese version of the Montreal Cognitive Assessment (MoCA-J) was used for cognitive assessment, and a decline of ≥ 2 points was defined as cognitive decline. Multiple logistic regression analysis was used to investigate the association between stroke and other risk factors with cognitive decline during a 3-year follow-up.Results Rates of cognitive decline increased in advanced ages, equaling 33.3, 39.4, and 66.7% in those aged 70, 80, and 90 years old, respectively. The fit of the hypothesized model by multiple logistic regression showed that a history of stroke, advanced age, and greater MoCA-J score at the baseline were important risk factors, while the presence of dyslipidemia and a higher educational level were protective factors that were significantly correlated with cognitive decline during the 3year follow-up. ConclusionsThe cognitive decline after the 3-year follow-up was influenced by the history of stroke, advanced age, and greater MoCA-J score at the baseline, but protective factors were the presence of dyslipidemia and a higher educational level. Therefore, these factors are considered important and should be taken into consideration when searching for creative solutions to prevent cognitive decline after stroke in community dwelling older and oldest people. 4