Human immunoglobulin G administered intravenously or subcutaneously is used to prevent infections in patients with primary antibody deficiencies. Intravenous immunoglobulin (IVIG) preparations have improved over the years and have evolved from immune serum globulin that is injected intramuscularly or subcutaneously at relatively low doses (100-150 mg/kg per month). IVIG products are currently available in different concentrations and compositions and can deliver up to 2 g/kg or more per infusion with few side effects. This report describes the properties and clinical trial results of BIVIGAM(®), a new IVIG product. We also discuss how improvements in intravenous immunoglobulin manufacturing and formulation have improved clinical outcomes in patients with primary immunodeficiencies, also benefiting patients with other immunological disorders.