The clinical syndrome of heart failure is very common in women. In fact, the majority of heart failure patients in the general population are female, in particular elderly women and women with a preserved ejection fraction. There are differences between heart failure in women and men in terms of epidemiology, pathogenesis, treatment response, and quality of care. The incidence is greater in men, but the prevalence at more advanced ages is higher in women. Prognosis seems to be better in women, although the mechanism responsible is not well understood. Clinical trials of heart failure have included fewer women than men, and this has limited our understanding of the efficacy of heart failure treatment in this group of patients.