Background Cognitive impairment may increase the risk of all-cause and cardiovascular disease ( CVD ) mortality. This study examined the association between cognitive function and risk of all-cause and CVD mortality among the elderly in Beijing, China. Methods and Results A total of 1996 participants aged ≥55 years at baseline were enrolled from the BLSA (Beijing Longitudinal Study of Aging). Cognitive function was assessed using the Mini-Mental State Examination ( MMSE ), and participants were categorized as: <18, 18 to 23, 24 to 27, and 28 to 30. Cox proportional hazard models were used to estimate the association. Hazard ratio ( HR ) and 95% confidence interval ( CI ) were reported. During a 20-year follow-up, 1122 (56.21%) participants died, 478 (42.60%) of whom died of CVD . Compared with MMSE scores of 28 to 30, participants with MMSE scores of <18 were independently associated with all-cause mortality ( hazard ratio, 2.14; 95% confidence interval, 1.59-2.87; P<0.001) and CVD mortality (hazard ratio , 4.52; 95% confidence interval , 2.80-7.30, P<0.001). Each 5-point decrease in MMSE score was associated with a 34% increased risk of all-cause mortality and a 56% increased risk of CVD mortality. This relationship remained statistically significant after using the competing risk model to consider non- CVD death as a competing risk event. Conclusion Cognitive impairment measured by MMSE score was associated with elevated risk of all-cause and CVD mortality among the elderly in Beijing, China.