Patients with combined primary immunodeficiency or B-cell deficiency with low serum concentration of immunoglobulin G can be efficiently treated with immunoglobulin G concentrates. From the 1950s IgG was used intramuscularly, and from the 1980s intravenous immunoglobulin (IVIG) replacement has become widely available for replacement therapy. Among the potential side effects of IVIG (including anaphylaxis), further disadvantages of IVIG are hospitalization during treatment and varying concentrations of IgG. Over the past ten years, subcutaneous IgG (SCIG) preparations have become reasonable alternatives to IVIG. SCIG given weekly assures a more balanced serum IgG level, side affects are mostly local and temporary, systemic, severe adverse events have not been observed. In addition, SCIG can be used for home treatment of patients which improves their quality of life remarkably. Orv. Hetil., 2011, 152, 64–67.