Recognition that heart failure (HF) is a major global health problem has led to widespread study of its causes, underlying mechanisms, associated co-morbidities and clinical characteristics. Most importantly, it has resulted in the development of therapies that greatly improve outcomes, particularly for patients with HF with reduced ejection fraction (HFrEF). Progress in understanding and treating HF, however, has been uneven with less robust advances seen in some areas than in others. One area that is lagging is the understanding of differences between men and women in several facets of HF, including pathophysiology, clinical presentation, management decisions and response to therapy. In this issue of the Journal, Frigerio and colleagues present an interesting case of a patient in whom the diagnosis and treatment of HF were greatly delayed. 1 While their lucid discussion attributes this to the patient's past history, her young age, and the presence of somewhat atypical symptoms, it is also possible that the patient's sex played a role. In this article, we discuss some of the gender differences in HF and their clinical implications.As summarized in Table 1, 2-6 there are important differences between men and women in the prevalence of risk factors for HF. Coronary artery disease (CAD) is, in general, the most strongly associated risk factor for HF with a population attributable risk (PAR) of 61%. 7 When gender differences are incorporated, however, the PAR for CAD is more than doubled in men compared to women at 39% and 18%, respectively. 8 In contrast, the PAR for hypertension, another common risk factor for HF, is higher in women than for men (59% compared to 39%). 8 Hypertension disproportionately affects women after the age of 65 years, with a threefold increase in risk of developing HF in this group, compared to a twofold increase in risk in men. 8 These differences play a role in determining well known sex and age differences in HF phenotype with HFrEF being more common and presenting at a younger age in males while HF with preserved ejection fraction (HFpEF) is more common in older women. Moreover, there is an interaction between sex and development of HF for some risk factors. Although diabetes mellitus is more common in men than in women, it has been associated with a fivefold increase in HF risk in women compared to only a twofold increase in risk in men. 9 In women with CAD, diabetes has been identified as the strongest predictor of HF. 10 Differences in the prevalence of risk factors have *Corresponding author. Advanced Heart Failure Treatment Program,