Long-term intravenous immunoglobulin (IVIG) infusion is an effective treatment for children with humoral immunodeficiencies, already be complicated by systemic adverse effects. In order to determine the adverse effects of intravenous immunoglobulin in patients with antibody deficiency, 45 immunodeficient patients receiving intravenous immunoglobulin were studied during a 36 month period at Children's Medical Center. The investigated group included 25 patients with common variable immunodeficiency, 14 patients with X-linked agammaglobulinemia and 6 patients with IgG subclass deficiency. A total of fifty adverse effects occurred through 955 infusions (5.2%). The most frequent immediate adverse effects were mild (40 infusions out of 955) in 22 cases, including: chills, flushing, fever, nausea and headache. Three patients experienced moderate effects (10 infusions out of 955) such as rash, severe headache, joint pain and chest tightness. None of the effects was anaphylactic type. It can be concluded that intravenous immunoglobulin is generally a well-tolerated medical agent for patients with antibody deficiency, but all patients should be monitored by a physician who is familiar with its indications, risks, adverse effects and their appropriate management.