Antibody deficiency may have genetic basis or be secondary to other diseases or iatrogenic factors. Recurrent respiratory, gastrointestinal and skin infections consist on the most frequent clinical picture. Severe course of these infections, recurrences and difficulties in treatment may suggest immunodeficiency. Antibody deficiency may be associated with numerous complications. Intravenous or subcutaneous immunoglobulin substitution is the way of treating these patients. Prevention of infection in primary and secondary antibody deficiency also includes vaccinations, prophylaxis with antibiotics and education of patients, parents and caregivers.