The first intravenous formulation of intravenous immunoglobulin (IGIV) was introduced in the United States in the early 1980s. At that time, the only indication was for treatment of primary immunodeficiency. By the mid-1990s, IGIV was mainly used for indications approved by the United States Food and Drug Administration, but as new indications are found, use of IGIVs is increasing. In fact, today, IGIV is mostly used for off-label indications. The specific characteristics of individual IGIV products must be directly addressed in the manufacturing process, as clinical efficacy may be affected. In addition, the safety profile of the ideal IGIV should be maximized by ensuring inactivation of the widest spectrum of viruses and prions. Some IGIV products are more suitable than others for certain patients; the challenge is to understand the different characteristics among products and select the most appropriate IGIV product for each patient. Convenience factors must be considered, for both the health care provider and the patient, without jeopardizing the more important features of the IGIV, such as tolerability and safety.