Approximately half of the nearly 5 million people in the United States who have heart failure (HF) are women. The vast majority of women with advanced HF are elderly and many of them have HF with evidence of normal or preserved left ventricular systolic function. Although coronary disease is a common cause of HF for both men and women, a history of hypertension or diabetes places a woman at particular risk. Many fewer women than men have been enrolled in trials of therapies for patients with HF. Sex-specific results have been reported for some of these therapies, but not all trial data have been analyzed for sex-related differences. In spite of these differences in outcome, cardiac transplantation remains an important option for women with very advanced HF. Future research on therapies for HF will need to target women for enrollment, and all data analysis should include results that are stratified by sex.