The development of vaccination is a major achievement in modern medicine. However, children treated with immunosuppression may not at all, or only in part, receive routine immunization due to uncertainty of its risks and effect. There is a substantial lack of pediatric studies concerning the efficacy and safety of vaccination in this patient group. Experience from similar adult groups and children with HIV infection can be used as a model for other disease categories. With increasing knowledge of the immunologic basis of vaccination and how immunosuppressive drugs interfere with the immune system, improved vaccines could be tailored, and adequate, individualized guidelines issued.