The objective of this paper is to present the process of the national and international accreditation leading to the establishment of the first certified chimeric antigen receptor T (CAR-T) Cell Unit in Poland on the basis of the Department of Hematology and Bone Marrow Transplantation in Poznan University of Medical Sciences and first successful CAR-T therapy in Poland. During 12 months from the initial decision to establish the CAR-T Cell Unit to the application of CAR-T cell treatment in the first patient, the center had to undergo the multidisciplinary external and internal training, as well as the adaptation of multiple procedures within the Transplant Unit and Stem Cell Bank. In order to get accreditation for the implementation of CAR-T cell therapy, an initial training of the team involved in handling cellular products and patient care was organized and updated as a continuous process. The Department fulfilled the site-selection international criteria. The first patient diagnosed for refractory/relapsed DLBCL was qualified, and finally CAR-T cells were administered with successful clinical outcome.