Intravenous immunoglobulin (Ig IV) has been used for many years in the treatment of primary antibody deficiencies. We performed a retrospective study of the clinical features and outcome of agammaglobulinemia children who received prolonged Ig IV infusions.Ten children, 9 male et 1 female, with agammaglobulinemia diagnosis were studied for the clinical manifestations before and during the Ig IV replacement therapy. Serum Ig levels were quantified by nephelometry. Circulating B ant T cells were counted by immunofluorescence labeling by monoclonal antibodies. T-cell functions were assessed by using mitogen and antigen -induced T-cell proliferation assays in vitro. Patients clinical status was evaluated respectively, before initiation and at every moment (when patients had an infection) of the replacement therapy.Ig IV therapy was performed for 866 cumulated months, median 108 months. The median Ig IV doses administered to the 10 patients was 500 mg/kg/month. Residual serum IgG mean level was 3,9 g/L. All patients had 99 bacterial infections/year before Ig IV, mainly respiratory tract infections (48,5%), and 4 patients had bronchiectasis before Ig replacement therapy. The number of infection/year fall to 25 during IgIV replacement, and the infection/patient/year rate decreases significantly. One patient developed an Echovirus 27 meningoencephalitis during this treatment.Ig IV therapy with residual IgG mean level of 3,9 g/l reduced significantly the rate of bacterial infections. The use of specific antibiotherapy and respiratory kinesitherapy led to a lower rate of respiratory tract infections, and the stabilisation of the bronchiectasis. However this intravenous replacement therapy does not protect against viral meningoencephalitis.