Introduction: Iron deficiency (ID) is often present (32% - 65%) in patients with heart failure (HF). Oral iron absorption in patients with HF is generally poor. This is the reason why oral treatment is not recommended. Aim: To test whether oral iron succinate significantly increases iron deposits in non-anaaemic patients with HF. Methods: ID was defined as ferritin < 100 μg/L or 100 - 299 μg/L with transferrin saturation (TSAT) < 20%. Forty-two patients were screened. Ferrous succinate was administered as one tablet (100 mg, including 32.48 mg Fe²⁺ plus 100 mg succinate) in the morning and one tablet at bedtime for at least 3 months. Hemoglobin, CRP, ferritin, iron, TSAT, and hepcidin were analyzed before starting treatment, at 6 weeks, and at 3 months end of study (EOS). Results: Five women and 15 men were included in the study. The level of ferritin increased significantly from baseline to 6 weeks (47 to 78 μg/L, p = 0.009) and baseline to EOS (47 to 85 μg/L, p = 0.001). TSAT increased significantly from baseline to 6 weeks (20% to 27%, p = 0.046) and baseline to EOS (20% to 25%, p = 0.043). Hepcidin increased significantly from baseline to 6 weeks (2.5 nmol/L to 4.8 nmol/L, p = 0.006) and baseline to EOS (2.5 to 4.2 nmol/L, p = 0.02). Conclusion: Oral iron succinate significantly increased iron uptake, almost doubling the ferritin levels and increasing the TSAT, in patients with HF. Our findings challenge the opinion that oral iron treatment cannot significantly increase iron deposits in non-anemic patients with ID and HF.