The main histocompatibility system in humans, known as the HLA system, is one of the most polymorphic gene systems whose products are destined to participate in immune reactions. The genes of the HLA system are located on the shorter arm of chromosome 6 and are divided into 3 gene regions. One of the most significant features of the HLA system is its association with autoimmune, nephrological, neurological and dermatological diseases. The most important significance is the connection of this system with tissue and organ transplantation. The HLA system is an essential part of any transplant program. The aim of the paper is to point out the importance of checking the cross-probe test when selecting recipients of possible cadaveric kidney donors. Special emphasis is placed on the positive results of the cross-probe test, as they indicate an absolute contraindication for cadaveric kidney transplantation. Before performing the cross-probe test, it is necessary to perform HLA typing of all loci of the potential donor and register in the ENIS system of Eurotransplant. Typing of the HLA locus of a potential kidney donor is performed using a serological method, and the results are confirmed using molecular methods including PCR-SSO (Luminex method) and PCR-SSP method. Based on the HLA typing of the potential kidney donor, a list of possible kidney recipients was sent from Eurotransplant. The list is based on matching of blood group, HLA typing and percentage of panel reactive antibodies. The results showed that one of the 4 possible kidney recipients had a positive cross-match. The patient was highly sensitized, and the typing of the possible recipient in relation to the donor showed a high discrepancy.