Galectin-3 is a soluble β-galactoside-binding lectin released by activated cardiac macrophages. Elevated levels of galectin-3 have been found to be associated with adverse outcomes in patients with heart failure. A number of recent studies suggest that galectin-3 may provide relevant information regarding the pathophysiologic process of heart failure. We analyzed the most recent and comprehensive studies which are focused on the association between galectin-3 and heart failure. Galectin-3 has also been associated with acute and chronic heart failure. Although most of the studies involved patients with heart failure and systolic dysfunction, galectin-3 seems to have more accurate role in heart failure with preserved left ventricular ejection fraction. However, the mechanism of this relationship and its clinical implications remain uncertain. Some studies have not been able to prove the association between galectin-3 and heart failure, so there are many questions to answer. Galectin-3 has also been involved to renal dysfunction, so it could be a mediator of worsening renal function. Serial measurement of galectin-3 could provide further prognostic information in heart failure patients.