Management of immunodeficient patients includes monitoring of growth, diet, personal hygiene and life habits, including environmental factors. Major therapeutic stays are prevention, early detection and the decisive treatment of infections. Attenuated live vaccines, non-irradiated blood products and blood containing CMV antibodies should not be applied. In the case of antibody defects immunoglobulin substitution is a specific form of treatment. Enzyme replacement is a causal approach to an adenosine deaminase defect. For numerous primary immune defects, bone marrow transplantation represents the best causal therapeutic measure. In the absence of a bone marrow donor, alternative gene therapy is available for the management of severe combined immunodeficiency on the X-chromosome (X-SCID), and adenosine deaminase deficiency (ADA deficiency).