Intravenous iron offers a rapid means of iron repletion and is superior to oral iron in many circumstances, especially in the presence of anemia of chronic disease, where it appears to overcome the block to absorption of iron from the gastrointestinal tract and immobilization of stored iron. The clinical situations where high doses of iron are commonly required are reviewed. These include nondialysis-dependent chronic kidney disease, inflammatory bowel disease, obstetrics, menorrhagia, and anemia associated with cancer and its treatment.