Background—Although higher optimism has been linked with an array of positive health behaviors, biological processes, and cardiovascular outcomes, the relationship between optimism and heart failure has not been examined. In the United States, 80% of heart failures occur in adults aged 65+. Therefore, we examined whether higher optimism was linked with a reduced incidence of heart failure among older adults. Methods and Results—Prospective data were from the Health and Retirement Study, a nationally representative study of older U.S adults. Our sample included 6,808 participants who were followed for four years. Multiple logistic regression models were used to assess if optimism was independently associated with incident heart failure. We adjusted for sociodemographic, behavioral, biological, and psychological covariates. Higher optimism was associated with a lower risk of incident heart failure over the follow-up period. In a model that adjusted for sociodemographic factors, each standard deviation increase in optimism had an odds ratio of 0.74 (95% CI, 0.63-0.85) for heart failure. Effects of optimism persisted even after adjusting for a wide range of covariates. There was also evidence of a dose-response relationship. As optimism increased, risk of developing heart failure decreased monotonically, with a 48% reduced odds among people with the highest versus lowest optimism. Conclusions—This is the first study to suggest that optimism is associated with a lower risk of heart failure. If future studies confirm these findings, they may be used to inform new strategies for preventing or delaying the onset of heart failure.