Heart failure (HF) is an important cause of morbidity and mortality. Obesity is an increasingly prevalent condition that has been associated with increased cardiovascular risk, including increased risk of developing HF. Based on the associations of obesity with cardiac structural and hemodynamic alterations, as well as case reports of reversal of cardiomyopathy with weight loss, obesity has been presumed to have a deleterious effect in patients with HF. However, several recent studies have shown that in patients with established HF, obesity is not associated with increased mortality, but rather is associated with improved survival. Potential mechanisms for cardioprotection in obesity include a diminished activation of the neurohumoral system, an enhanced protection against endotoxin/inflammatory cytokines, and an increased nutritional and metabolic reserve. Further investigations into the relationship between obesity and the progression of HF are necessary. Ultimately, clinical trials are needed to provide definitive guidance to the management of obese and overweight HF patients.