Heart failure is a risk factor for Alzheimer's disease and cerebrovascular disease. In the absence of heart failure, it was hypothesized that left ventricular ejection fraction (LVEF), an indicator of cardiac dysfunction, would be associated with preclinical brain magnetic resonance imaging (MRI) and neuropsychological markers of ischemia and Alzheimer disease in the community. Brain MRI, cardiac MRI, neuropsychological, and laboratory data were collected from 1,114 Framingham Heart Study Offspring Cohort participants free from clinical stroke or dementia (aged 40 to 89 years, mean age 67 ± 9 years, 54% women). Neuropsychological and neuroimaging markers of brain aging were related to cardiac MRI-assessed LVEF. In multivariable-adjusted linear regressions, LVEF was not associated with any brain aging variable (p values >0.15). However, LVEF quintile analyses yielded several U-shaped associations. Compared to the referent (quintile 2 to 4), the lowest quintile (quintile 1) LVEF was associated with lower mean cognitive performance, including Visual Reproduction Delayed Recall (β = -0.27, p <0.001) and Hooper Visual Organization Test (β = -0.27, p <0.001). Compared to the referent, the highest quintile (quintile 5) LVEF values also were associated with lower mean cognitive performance, including Logical Memory Delayed Recall (β = -0.18, p = 0.03), Visual Reproduction Delayed Recall (β = -0.17, p = 0.03), Trail Making Test Part B - Part A (β = -0.22, p = 0.02), and Hooper Visual Organization Test (β = -0.20, p = 0.02). Findings were similar when analyses were repeated excluding prevalent cardiovascular disease. In conclusion, although these observational cross-sectional data cannot establish causality, they suggest a nonlinear association between LVEF and measures of accelerated cognitive aging.