Hypersensitivity reactions (HSRs) to intravenous iron preparations (IVIPs) are well known. With newer preparations, HSRs have become rarer; however, severe reactions may still occur. We retrospectively reviewed records of patients evaluated for HSRs to IVIPs, to determine the safety of controlled re-administration (CRA). Allergological work-up included a detailed history, skin prick tests (SPTs) with IVIP, and basophil activation tests (BATs) in some patients. CRA with an IVIP was carried out if indicated. Thirty-one patients with mild to severe reactions were evaluated. SPTs and BATs were negative in all patients tested. Eighteen CRAs in 15 patients were performed. Twelve patients tolerated the procedure, including three with a previous grade IV HSR. Two developed urticaria and one developed urticaria and dyspnea. The pathophysiology of HSRs to IVIPs remains currently unclear. SPTs and BATs provided no additional information. However, in appropriate situations, CRA under surveillance can be safely performed in most patients.