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.