An impairment of all spleen functions is a matter of course in both congenital asplenia and asplenia caused by an injury to the spleen. There also exists a group of diseases which result in asplenia or functional hyposplenia. Absence or dysfunction of the spleen brings a higher risk of life-threatening infection. Preventive procedures for patients with congenital, acquired or functional asplenia involve three basic types of activity: vaccinations, chemoprophylaxis, and educating patients, their parents and medical personnel. In this paper we present recommendations for prevention of life-threatening infections in this group of patients.