Despite the known associations between preoperative anemia (particularly iron deficiency anemia) and poor postoperative outcome, recent evidence suggests that administering intravenous iron relatively close to surgery does not yield a tangible short-term benefit. This is made more complex by the interplay between iron and innate immunity. Iron deficiency irrespective of hemoglobin concentration may also impact postoperative outcomes. Therefore, further research into associations between iron deficiency and postoperative outcomes, and between postoperative anemia, delayed outcomes (hospital readmission), and the efficacy of postoperative intravenous iron is required.