BACKGROUND: Limited evidence comparing different intravenous (IV) iron products is available to guide the optimal IV iron product in patients with heart failure (HF) and iron deficiency (IDef). OBJECTIVES: To compare ferric carboxymaltose (FCM) with iron sucrose in patients with HF with reduced or mildly reduced ejection fraction. METHODS: This single-center retrospective cohort study included patients with HF with reduced or mildly reduced ejection fraction and IDef who received either FCM or iron sucrose. The primary outcome was IDef therapy goal achievement (defined as ferritin 100-300 mcg/L and iron saturation > 20%; ferritin > 300 mcg/L; or hemoglobin > 15 mg/dL regardless of iron study). RESULTS: A total of 78 patients in the FCM group and 21 in the iron sucrose group were included. The use of FCM was significantly associated with a higher rate of IDef treatment goal achievement after the induction course than iron sucrose (70.1 vs. 41.2%, p = 0.026). After adjusting for multiple variables, FCM use was significantly associated with a higher rate of the primary outcome than iron sucrose (adjusted OR 5.8 [95% CI 1.3-26.1], p = 0.022). No significant difference in adherence to the IV iron criteria was found between the two groups (80.8 vs. 81.0%, p = 0.985). CONCLUSION: Ferric carboxymaltose use was associated with a higher iron repletion rate than iron sucrose in patients with HF with reduced or mildly reduced ejection fraction and IDef.