Severe combined immunodeficiency (SCID) is a heterogeneous group of rare genetic disorders caused by a number of different gene mutations and characterized by impaired humoral and cellular immunity. Affected infants usually present in the first months of life with atypical or recurrent infections. If left untreated they mostly die by the end of the first year of life. SCID is a rare disorder and that is why a high degree of suspicion is necessary to enable early recognition and diagnosis. A complex immunological investigation should be always indicated in children with recurrent skin and mucosal infections, respiratory and gastrointestinal infections and failure to thrive, mainly in combination with persistent lymphopenia. Hematopoietic stem cell trans plantation (SCT) is the current treatment of choice for most of the forms of SCID. Immunoglobulin substitution and treatment with wide-spectrum antibiotics, antimycotics, antituberculotics and antivirotics must be commenced once a diagnosis of SCID is made. Only irradiated blood products can be administered to these children. Relevant issues related to early recognition and diagnosis are demonstrated through nine čase reports of patients with severe combined immunodeficiency diagnosed and indicated for SCT in the Czech Republic in 1995-2004. Hematopoietic stem cell transplantation is the most effective treatment in patients with SCID and early diagnosis and urgent referral to a specialized center is crucial for successful outcome of SCT.

        Key words: severe combined immunodeficiency, primary immunodeficiency, infec-tion, stem cell transplantation