Preoperative anemia affects 30–40% of patients undergoing major surgery and is an independent risk factor for perioperative blood transfusion, morbidity, and mortality. Absolute or functional iron deficiency is its leading cause. Nonanemic hematinic deficiencies are also prevalent and may hamper preoperative hemoglobin optimization and/or recovery from postoperative anemia. As modifiable risk factors, anemia and hematinic deficiencies should be detected and corrected prior to major surgical procedures. Postoperative anemia is even more common (up to 80–90%) due to surgery-associated blood loss, inflammation-induced blunted erythropoiesis, and/or preexisting anemia. Preoperative oral iron may have a role in mild-to-moderate anemia, provided there is sufficient time (6–8 weeks) and adequate tolerance of oral preparations. Postoperative oral iron is of little value and rife with gastrointestinal adverse events. Intravenous iron should preferentially be used in cases of moderate-to-severe iron deficiency anemia, concomitant use of erythropoiesis-stimulating agents, short time to surgery or nonelective procedures, and for postoperative anemia management. Minor infusion reactions to intravenous iron are rare, the incidence of severe anaphylactic reactions is extremely low, and there is no increase in infections with intravenous iron. Currently available intravenous iron formulations allowing administration of large single doses are preferred.