Background: Congestive heart failure is the leading cause of hospitalization in the elderly. Little is known about gender effect on baseline characteristics and in-hospital outcome in patients admitted with acute heart failure. Our purpose was to study the gender effect on in-hospital mortality in acute heart failure patients. Methods and Results: A prospective study [143 patients, 67 men (73.9 ± 13.8 years old) and 76 women (77.8 ± 10.1 years old) (p = 0.059)] followed in-hospital outcome of patients with acute heart failure admitted to the hospital. Clinical parameters included body mass index (BMI), ankle brachial index (ABI), left ventricular ejection fraction (LVEF), re-admissions within 1 year, and in-hospital mortality. The gender effects that were studied included height, BMI, smoking, coronary artery disease, LVEF and mortality: in total, 9 (6.3%) patients died, of them 8 (10.5%) women and 1 (1.5%) man. Women were shorter (p < 0.001), had a higher BMI (p = 0.053), reported less frequently on current smoking (p < 0.001), had lower prevalence of coronary artery disease (p = 0.016), had a better LVEF (p = 0.02), but still, had a higher mortality rate (p = 0.026). The only variables independently affecting in-hospital mortality in women were height and recurrent admissions. When we tested for the effect of height and recurrent admissions on mortality only among females by a multivariate analysis height inversely and independently affected in-hospital mortality (p = 0.024), as well as recurrent admissions (p = 0.031). Conclusions: In-hospital mortality was significantly higher in women compared with men admitted with acute heart failure. Among females, the only independent variables that affected mortality were low stature and recurrent admissions.