This is the first prospective study of adverse reactions occurring in primary-antibody-deficient patients self-infusing intravenous immunoglobulin at home. One hundred nineteen patients, already self-infusing at home, were entered into the study. They had been fully instructed about all aspects of adverse reactions, including their prevention and treatment. In the event of any adverse reaction, a form was completed detailing the product, the dose, the symptoms that occurred and the time they lasted, the rate of infusion, and other relative information such as predisposing factors and any medication taken. The severity of reactions were classified as mild, moderate, or severe. The total number of reactions documented was 19 in 2031 infusions, and all resolved without medical aid. No serious reactions occurred. Excluding those reactions in which predisposing factors were identified, the overall reaction rate was 0.7%. In conclusion the study showed the reaction rate in patients self-infusing intravenous immunoglobulin at home was low following formal training of selected patients at recognized training centers.