Iron deficiency (ID) is one of the most common comorbidities in patients with heart failure (HF). ID is a strong independent predictor of outcomes in HF patients. ID reduces quality of life, exercise tolerance, and survival in patients with HF, regardless of anemia status. The latest 2021 guidelines recommend initiating ID treatment at a ferritin <100 µg/L, or 100 to 299 µg/L, when transferrin saturation is less than 20%. The FAIR-HF and CONFIRM-HF studies have shown improvements in symptoms, quality of life, and functional status in patients with stable HF and ID after intravenous administration of ferric carboxymaltose (FCM). Moreover, the results of these studies showed a reduced risk of hospitalization for HF, which was later confirmed in a subsequent meta-analysis. Finally, the AFFIRM-AHF study, which evaluated the effect of FCM administration on outcomes in patients hospitalized for acute HF/acute decompensated HF, found a significant reduction in HF-related readmissions among patients treated with FCM.