BACKGROUND: Higher rates of obesity and heart failure have been observed in African Americans, but associations with mortality are not well-described. We examined intermediate and long-term clinical implications of obesity in African Americans and associations between obesity and all-cause mortality, heart failure, and heart failure hospitalization. METHODS AND RESULTS: We conducted a retrospective analysis of a community sample of 5292 African Americans participating in the Jackson Heart Study between September 2000 and January 2013. The main outcomes were associations between body mass index (BMI) and all-cause mortality at 9 years and heart failure hospitalization at 7 years using Cox proportional hazards models and interval development of heart failure (median 8 years' follow-up) using a modified Poisson model. At baseline, 1406 (27%) participants were obese and 1416 (27%) were morbidly obese. With increasing BMI, the cumulative incidence of mortality decreased (P= .007), whereas heart failure increased (P < .001). Heart failure hospitalization was more common among morbidly obese participants (9.0%; 95% confidence interval [CI] 7.6-11.7) than among normal-weight patients (6.3%; 95% CI 4.7-8.4). After risk adjustment, BMI was not associated with mortality. Each 1-point increase in BMI was associated with a 5% increase in the risk of heart failure (hazard ratio 1.05; 95% CI 1.03-1.06; P < .001) and the risk of heart failure hospitalization for BMI greater than 32 kg/m(2) (hazard ratio 1.05; 95% CI 1.03-1.07; P < .001). CONCLUSIONS: Obesity and morbid obesity were common in a community sample of African Americans, and both were associated with increased heart failure and heart failure hospitalization.