BACKGROUND: Iron deficiency is the most common single cause of anemia worldwide. Treatment consists of improved nutrition along with oral, intramuscular or intravenous iron administration. OBJECTIVES: To describe the efficacy and adverse effects of intravenous iron sucrose therapy in a group of children with iron deficiency anemia who did not respond to oral iron therapy. METHODS: We conducted a prospective investigation of 45 children, aged 11 months to 16 years, whose oral iron therapy had failed. The children attended the Pediatric Day Care Unit where they received intravenous iron sucrose infusion. RESULTS: Forty-four of the 45 patients were non-compliant. Nine had Helicobacter pylori gastritis and 16 patients suffered from intestinal malabsorption from different causes. Before treatment, the blood mean hemoglobin concentration was 7.43 g/dl (range 5-10.1 g/dl). Fourteen days after treatment it increased to 9.27 g/dl (SD 1.23) and 6 months later to 12.40 g/dl (SD 1.28). One patient demonstrated a severe side effect with temporary and reversible reduced blood pressure during treatment. CONCLUSIONS: These preliminary data suggest that administration of intravenous iron in pediatric patients is well tolerated and has a good clinical result, with minimal adverse reactions.